Doubling is twice.

record a vocal line twice, in tune and as close to the phrasing of the original take as possible and then mix evenly.

many variations but that's the basic idea.

Now that many of you have a DAW you can edit like mad and cut/paste from other parts of the song and bump words ...

remember that the same bit of audio in the same place does nothing but increase the volume.
Same but shifted in time can cause artifacts / comb filtering.

but some people love it so much they double track everything.

You can use a short single delay to get what is called ADT (artificial double track).
... +/- 50 msec delay and a big part of the typical John Lennon sound.
... for those that are a bit lazy.

thank you for the information!!! I had an idea that Voice doubling was what I was doing but I wasn't sure if that is what you guys were referring to when you said it... Anybody else? oh and I'm still looking for some samples...

Samples? Just listen to any modern rap track, or just about any modern pop track for that matter. Turn on the radio to a top 40 station and there it will be. What do you have down there again? 96 WSTO is it? Better yet, try it! Do as Kev says. Try mixing the double in lower in volume than the original take. Try panning one slightly left and one slightly right to widen the image. Try panning them hard left and hard right. Try pitch shifting one up a couple of cents and the other one down. Try everything.

It's all about experimentation isn't it? good stuff - thanx

David French wrote: Try pitch shifting one up a couple of cents and the other one down. Try everything.

yep
try everything and on all things. not just voice.

in days gone by we used to tweak the speed/pich knob of the tape deck when doing a vocal O/D then return the knob to set. This gave the Original and the Doubled a light pitch chorus twelve string guitar sort of thing.

just keep experimenting
don't just listen to us
invent new ideas

it's all good