How To....(long)
Whee. I'm having fun. I've entered Devoted Defender into the database. Most of it was pretty straightforward.
I'm going to write down a broad outline of how to do it here, but please keep in mind I regard it as a draft!

(The order of this may seem counter-intuitive, but I chose it so that you don't have to hop table to table, instead you create the things that will be referenced by another table first).
0) Read the Prestige Class thoroughly to make sure you understand all it's weirdnesses.
1) Look for things that e-Tools calls "Feature Groups" in the devoted defender, there are three of these, for example:
Defensive Strike (which initially has no bonus, and then progresses to +1, +2, +3, and finally +4 at 10th level)
Deflect Attack (progresses from +1 to +4)
AC Dodge Bonus (progresses form +1 to +5)
If the prestige class has something like that, you'll probably want a Feature Group added to the table "lookup Feature Group". A very straightforward table with 2 fields: an id field (just make it one bigger), and the Feature Group field. For Defensive Strike, I made the Feature Group "Defensive Strike". I'd keep it obvious like that unless there is a duplication issue.
2) Next, I'd probably take care of the info Features table (do not confuse with info Feat!)
The info Features table has about six fields:
1st) Id (make it one bigger than the biggest)
2nd) Guid (let access generate this for you)
3rd) Name. If the feature isn't one of the ones you identified needing a "feature group" then you simply put the feature name here, such as "Harm's Way", "Uncanny Dodge" etc.
If it's a Feature group one, you'll want something like this: "Defensive Strike +%d". The %d will be the number that's filled in later on....
4th) Feature Group: If you've defined a Feature Group for it, fill it in here, otherwise, put "None"
5th) Type: Usually None, Feat if it's a free FEat, Favored Enemy if it's the Favored Enemy feature, etc. Look at the other records to get an idea of what goes here for your feature.
6th) HelpText: Some descriptive text shown to the user when clicking on the feature.
3) Next Stop: "info Class"
Many fields here, most are self explainatory. Id you make one bigger, the guid you let access generate for you, Name is the name of the class, ClassType should be Prestige Class for Prestige classes, PlayerClass for a new core class, or NPC for a new NPC class. HitDieType, d4,d6,d8,d10,d12 as appropiate. AgeCat is for determining the base age (not relevant for Prestige Classes). The next three checkboxes determine the saves...checked, it's a good save, unchecked it's a "poor" save.
One that may be counter-intuitive is "BaseAttackMultiplier"
If it' has the "Best Attack" (like a fighter), put a 1. If it has "mediocre (sp?)" attack, put .75 (like a cleric), if it has the "poor" attack (like a wizard), put .5.
The next six fields determine the relative priority of the stats (I'm not sure what this is used for, but I used the other classes as guides
SkillPointsPerLevel should be obvious. Unless you have class that is like the Loremaster, ignore "ClassSkills" and "ExclusiveSkills". The next three fields after that determine starting gold (not relevant for prestige classes, set to 0, d1 and 0)
Next few fields are fairly self-explaintory, they control the various spellcasting abilities of the class. I've not done a magic-using class yet, so I don't know of any weirdnesses here.
Shortly after that, there is a few checkboxes determining proficiency in various proficiency groups. If you're working with a class that has a list of specific weapons, like the druid, you'll need to visit the "info Class Weapon Proficiency" table.
After that is a series of fields I don't fully understand yet, but appear to be related to "Monster Advancement" (feats/level, skills/level, etc.)
4) Whew. Still here? Next Step: info Class Features
The first is the "ClassID". This is the name of the class that you put in the "name" field of the "info Class" table.
The 2nd is the Level that the character "receives" the feature that you're entering.
The 3rd is "FeatureID" which you'll want to put the exact same name you gave the feature on the info Features table. If you put "Harm's Way" put "Harm's Way", if you put "Defensive Strike +%d", don't leave out that +%d...it must match!
The 4th is the "Data" field. If you are adding a feature to the list that is a member of a feature group, you'll want to put it's variable data here. For example, for the Defensive Strike feature, I entered Defensive Strike 5 times, each with a different number in the data field.
The 5th is the "DataGuid" field. Usually all 0's (copy from another). If you're confident it works identically to another, you may want to copy that guid instead (for classes that have a feature in common, usually)
The 6th is a "notes" field, which appears to be a "notes to self" type of field.
After that, it's pretty straightforward:
If there is alignment restrictions, visit "info Class Alignment Restrictions" and add a row or two as needed...NOTE this differs from a prestige classes "required" alignment. See "info Class Requirements" for that (below)
info Class Skill Usability is a simple list of "Class" and "Skill". You'll want an entry for each skill the class has as a class-skill.
info Class Requirements is where you set feat, skill requirements, Race requirements, etc.
This is one of the few places I ran into trouble. I couldn't discern how to deal with the "Weapon Focus (any)" requirement of the devoted defender, so I've left it out for now. The Arcane Archer has a similar requirement (Weapon Focus (any bow, not crossbow), and I note that it's not on this table either. I suspect they ended up writing a bit of code special for the AA.
Otherwise, the table was fairly straight forward:
Id: ClassId/Name (same as one on table info Class)
Requirement: type of requirement: race, alignment, skillsimple, featsimple baseattack
Race: If it's a race requirement, race goes here, otherwise "none"
FeatId: If it's a feat requirement, the feat goes here (has to match then name on the "FEats" table
SkillId: If it's a skill requirement the skill name goes here (has to match the name on the skills table)
Alignment: If it's ....I think you get the picture.
Data: If there is a numerical requirement (usually skill or BaseAttack requirements) it goes here. Devoted Defender need 4 in spot, so I put 4 here when I was entering the spot skill requirement.
Whew...that turned into alot more typing that I expected, but hopefully that gives everyone a better insight on how to tamper with their database to add a prestige class.
Feaelin.