First, a belated welcome to FlyerTalk!
As the posts above point out, there is a large, modern TGV station built as part of the Terminal 2 complex (which serves mainly Air France and its partners).
You, along with your luggage loaded on a rolling cart, can reach the station via moving sidewalks and other interior walkways, so you are protected from the elements in case the weather is bad.
One important issue is, where is your destination? Not all TGV destinations are served from the CDG station (at least not directly). To give one example, I travelled Geneva to Paris some time back. I was able to go on a single TGV from Geneve to Paris without changing or transferring, but to the Gare de Lyon, NOT to CDG.
If I had wanted to go directly to CDG, I would have had to changed in Lyon (non-TGV from Geneve to Lyon, then transfer to a TGV from Lyon to the CDG station).
More information is on the French Rail (SNCF) site, this link should point to the english language version:
http://www.sncf.com/indexe.htm
Good luck and safe travels ...
NNR
[This message has been edited by Non-NonRev (edited 11-06-2000).]