Starting at level 0

[Aus_Snow]

Thanks for posting the link. Yep, that's the one.

 

[Li Shenron]

Yes, the 3.0 DMG has rules for this. The intent may have been to allow a 1st-level character to have two classes, I can't remember, but certainly it could be used to have only half a class. If you'd like I could try to dig those rules up for you.

These are very easy and work quite well.

You can either use them to make a 0th-level character, or combine two "0-levels" of different classes to get a 1st level multiclass ("half level" in each class).

 

[Angel Tarragon]

You might want to check this out.