Hi, guys!
"Prost" and "zum Wohl" are interchangeable, and mean basically the same thing.
"Prost" is actually a contraction of the Latin "prosit", which means, "may it benefit (you)" or "may it help (you)". "zum Wohl" means "to (your) health".
They can be used either with beer or with wine, and also, as Sgt Schultz once said, "Don't forget the Schnapps!"
When I joined the forum, I had a flash to use that as my signature, it seemed fitting, given my background and my interest in German language, culture and history. So, my sign-off when I post became, "Prost!", or when I'm feeling bairisch, "Prost, beianand!"
Also, prost, meine Freunde!
Brad