ASIC, or Application-Specific Integrated Circuit, does pretty much what the name suggests. It does one calculation very efficiently.
FPGAs, or Field-Programmable Gate Arrays, are kind of a cross between GPUs, which are able to do relatively general computing, and ASICs, which are application-specific. FPGAs can usually do a small set of related tasks.
GPUs, compared to the two above, are most like a CPU. GPUs can do all sorts of different things, but in BTC mining, a lot of their hardware and instructions are going to waste, often even getting in the way of doing the actual mining. Nvidia and AMD/ATI do have their own "specialties," and this is why Nvidia cards are significantly worse at BTC mining than a similarly-priced ATI card, even though the Nvidia card could outperform the ATI card in other areas.
ASICs and FPGAs aren't really technological progressions beyond GPUs, just specialized hardware which has taken over the mining ecosystem due to their high efficiency, and the very specialized task required to hash in BTC.
You would be better off not trying to mine with GPUs, as difficulty is soaring (35-50%/month) due to ASICs finally being delivered. Unless you have free electricity, you'll be paying much more for BTC than just snagging them off an exchange or from a peer.
With all that said - for Nvidia, you need drivers with CUDA (Idunno how Nvidia packages work -- maybe they all their drivers have them), and a CUDA GPU miner, such as
Poclbm.
@ latest Qs: You would probably NEVER find a block in your lifetime mining alone, so definitely go with a pool. Idunno if BitMinter supports CUDA, but you might want to try their one-click miner and see if it works for you @
http://bitminter.com/ (it uses Java, but at least for OpenCL and the Avalon FPGAs I ran with it, is usually on-par with performance with other less-user-friendly applications -- it's been around a long time... I wouldn't hesitate to trust the program's integrity, fwiw)
ETA: You might be able to mine an altcoin profitably -- something like Litecoin. Its difficulty is seeing the effects of BTC mining becoming too costly now that ASICs have been developed for it, and with an Nvidia card, it's very unlikely to be profitable - but I sure don't know dick about altcoins -- I barely know anything about BTC mining. Fwiw.
