I have a newly discovered allergy to sulfonamide (sulfa) drugs too. My allergist insists (and many web sources agree) that this does not make me prone to allergic reactions to either sulfur or sulfites. I believe I've had some wine with sulfites in it since then, and didn't have any problems. Apparently, these three chemical compounds are different enough that the immune system CAN tell the difference.
Like Denise, I just have to let all my medical folks know of the allergy, as meds are the only way I could encounter sulfa.
Here is a Mayo Clinic site listing a few other meds that may contain sulfa:
Co-Moderator, Anxiety and Panic Forum
DX: Anxiety, Depression, LPR (acid reflux)
Meds: Paxil, Nexium, Zantac