Ah... now here's a topic I can dig into. I've been recording audio for over 30 years and doing live sound for about the last 10 of those years. I can give you several "Old School" techniques as well as a few "New School" ones to boot.
Generally, 2 mics are a minimum to capture a balanced sound. 3 are better and of course one on each drum with a pair of stereo overheads is possibly the best, depending on what sound you're going for.
We'll stick with minimal mics for this though. As Tommy said, one overhead won't really pick up the kick, in all it's glory, so a proper kick mic is needed. This would be a mono setup, not stereo BTW.
For the overhead, use a good quality pencil type condenser mic. Prices start around $50.00 and your average $100.00 to $200.00 mic will sound pretty good. All condenser mics require phantom power (48 volts) and the cheapest way to get it is to buy a small mixer w/phantom power. Any of the budget mixers by Behringer , Alesis, etc... will do.
For the kick, you'll want a dedicated kick mic as opposed to a standard vocal mic. This should be a dynamic mic, not a condenser. Dynamics are more focused and will pick up less of the other bits in your kit. The AKG D 112 is an industry standard kick mic and in fact, I believe it's the mic used on TommyP's kick in his avatar. There are cheaper mics for this purpose - Just google "kick mic" and I'm sure you'll find plenty.
Placement is the next thing. The best mic will sound like poop if it's not placed in the proper spot. That said, there is no science to the proper placement of mics. You usually need to experiment a bit to find your own "sweet spot" on a given it. Start with the overhead centered above the kit, pointing down at a height of about 2 - 3 feet above your highest cymbal.
For the kick, you really need to play with the position to get the sound you want. Placing the mic into a port on the front head will yield more of the beater attack and less of the low end and shell. Move it back about 6 inched from the port and you'll get more thump and less beater. Place the mic dead center, about 6 inches from the head and you'll get some of the beater, plenty of low end, and less ring from the reso head.
On to the Old School techniques - I guess the simplest form of micing would be a single large diaphragm condenser or ribbon mic placed in front of the kit, about 4 - 5 feet high and about 6 or more feet away from the kit. This would give you an old school jazz sound from say, the 30's or 40's. Mic's were expensive back then so many studios had only a few on hand. The deal was... set up the mic and them move the musicians around the room till you got your balance right. Drums were usually the furthest away from the mic because they were loudest.
The problem with the one mic setup is that you need a good sounding room to start with. Small rooms are not a good choice for this technique as they generally sound boxy. Drums need a little space to breathe, in order to sound natural.
Another old school technique is the same as described above by TommyP. Many of the early Beatles recordings as well as many jazz recordings in the 60's were done this way.
The late 60's and early 70's saw the close multi-mic setup becoming popular. Reso heads were removed, mics were shoved up into the shells, lots of duct tape and napkins on the skins, etc... This is the thumpy, un-natural sound you hear on many rock records from this era. Funny that these days, we're going back to the simpler techniques where the mics are pulled back a bit from the kit to get a more "real" or natural sound from the kit.
Modern/semi-modern techniques - Popular today, the recorderman 2 mic technique is pretty decent sounding. Rather than explain it, here's a link to a video showing each step - [ame]http://www.youtube.com/watch?v=IiFOD1EeKhQ[/ame]
Add a kick mic to this setup, and you can fill out the bottom end of the sound a bit. Biggest tradeoff here is that your cymbals tend to be a bit overpowering unless you play with a light touch.
Wow! That's a lot of typing - LOL!!! Like I said, recording is my "other" passion, drumming being number one.
I'm in the process of tweaking the sound in my NEW recording studio so I'm playing around a lot with drums and mics. If anyone is interested, I can put up some sound files of the various techniques so you can hear for yourselves.