I'm a little confused...does "high" = slow, and "low" = fast?

On drums, either at track level or bus level--however it works out, I tend to use a faster release than I would on the master bus. For attack, I dunno. I can't really think of any guideline that I do most times. I guess fast enough that at least part of the drumhit is getting compressed, but slow enough to let some pop get through. I hardly ever use ultra-fast attacks, unless going for an effect.
Another one of those questions that requires a psychic answer. At some point you just gotta ask yourself, "Does this sound cool?" If you are unsure what sounds cool, then spend some more time listening to stuff that does, then spend some time playing around to find what settings work well for your particular situation to make things sound cool.

Reggie wrote: I'm a little confused...does "high" = slow, and "low" = fast?

be warned that some compresors aren't so obvious
front panels can be confusing

cw (clockwise) = more ... but can be
more time = slow
more spead = fast

annoying isn't it

very generally
go gentle on all parameters on the early comps working up to the tighter stuff on the final ones
:shock:
but that's very general

for those with experience and a very good idea of what they want in the final mix they may use hard limiting on kick and snare right at the start and clip the tops off the transients before going into the gate.

there is no easy one formular fits all sort of settings

Typically- you can use faster attacks and faster releases at the track level. Usually this is because you're trying to control transients of the specific track.
At the mix level, you're usually trying to control the overall level over time so that the track doesn't get overly loud at the loud passages. Similar to gently moving the fader up or down during the mix. Here you want slower attack and release times.
For beginners, you can get a better understanding of how compressors (and gates for that matter) work by not using them. When you're forced to mix with one hand on the fader,and an eye on the meter, you start to realize how attack, release, threshold and ratio start to play an organic role with the track. After tracking and mixing 20 or 30 songs this way, you start to find ways of moving the fader that produces consistantly good results. Then you start to wish you had a machine that could do those moves for you. You'll start to program your compressor to mimic what you've been doing with your hand. (hmmm I'm sure there's a better way to phrase that)

its important to visualized (or hearualize) what a compressor is doing. I have an analogy of a compressor actually being a little person named Compressor. Compressor's only job is to turn things down, and all of the controls are telling him when and how to do it. Threshold is when to start turning down, ratio is how much to turn down. Attack is how soon after he gets the signal to turn down he actually does it, and release is how long he waits to turn the signal back up. Especially with drums, you have to be careful wth your attack. Compressors at the track level, say a snare drum, are used to even out inconsistencies in the drummers velocity. If you have a very short attack, the compressor turns down immediately when the signal, which in the case of a drum is any signal, crosses the threshold. If you lengthen the attack, the initial part of the transient will make it through without being turned down, so the overall effect will be more even, but the character and dynamic in the playing are still there. both the attack and release should be set by ear; theres no specific rule. I usually dial in the threshhold and ratio with the attack relativeley low, and the release low also. Then i slowly raise the time of attack until I can hear the right amount of transient coming through uncompressed, then set the release based on the speed of the song.

For a drum bus, I use the same method. If you have very short attack, the only effect you get is turning the track down, and depending on the release, raising the level of everything thats not a drum hit, but if you lengthen the attack, you can take advantage of that thicker "between hit" sound with the initial transient still intact.

The master bus is all about program material, and there are a lot more factors than just the drums. It depends on what in your mix is controlling the overall loudness in the mix. This can be vocals, bass, drums, or whatever, so you're settings will have to reflect that.