To get the AD&D or OD&D experiance, your going to have to play AD&D or OD&D. Those games have a feel to them created by the intersection of their rules (as they play out) and their text and artwork. Those 3 components define that experiance. I disagree a bit with Foster when he says you can't go back. Sure I can't go back to the first 50 games when I didn't know what was going on, but I can continue experiancing the game pretty much as I did back then. Sure the mystery of how it works is gone, but thats true with any game (and in 3Es case there never was a mystery, the rules aren't hidden from teh player as they were in 1E). Anyhow if things get predictable, rotate DMs It gives the game a fresh feel.
AD&D is no different then Monopoly or Risk, its a table top game with out a board and people using their imaginations pretending to be the pieces more or less. Its playing "make believe" but with rules. And just as my experiance with Risk is pretty much identical to when I was a kid, so is AD&D. Rules are rules, its as simple as that. If your players don't have the 1E books OSRIC is an excellent second source (a duplicate rules system to 1E). It has a companion book in the works as well as a Monster Manual and a bunch of support modules. C&C is pretty good as well, but IMO still has to much of the D20 element floating around.
TForsters idea of getting a newbie is good. Best of all are those who have never played any FRPG but are familiar with fantasy. Girlfriends and wives are usually a good source for this (but thats not always easy, to most chicks who don't already game, we are a bunch of super-geeks when we play. So go slowly with it). We have 2 girls (wives) who were converted over time in this way. They are the ones who remember to do the obvious things our jaded "robotic" players forget about, and its the little things that make the game fun. It helps to see the excitement in someone elses face to recapture it yourself (kinda like getting to experiance your childhood again when people have kids).
If you want to retro your 3E game, good luck. I tried and found it impossible (fighters without feats, aint gunna happen). Even if you got the rules to produce old school results, you don't have Gygax's spirited text nor the wonderful mysterious black and white artwork that covered the PH and DMG. You also don't have the tables, another MUST for the old school feel IMO.
I managed to get my group to start playing 1E after 3 years of 3E by getting them to agree to a 1x a month AD&D game. It took about 3 sessions before people "figured out" all the stuff they hated about 1E was what was so great about it all along.
Now its all our group plays (we range from 2 to 6 players normally, sometimes going up to 10. An added bonus of AD&D over 3E is that you can run alot of players without slowing down the game much).