First some background:
I'm a classical guitar student at university. So, music is something that I'm pretty familiar with. Besides being a guitarist, I've always been fascinated with the percussion world. I've had some lessons in the past. (Just a little bit.)

My question:
I'm not really sure what I should be doing/practicing to improve. (Other than find a teacher. Which I'm currently looking for. Small town woes! ) I got some books: Stick Control by George Lawrence Stone, Progressive steps to Syncopation for the modern drummer by Ted Reed , and Drum Studies Concepts, reading, phrasing, and technique by Dave Vose.

What else should I be working on? What online resources are there?

It is required by law to own a copy of Jojo Mayer's Secret Weapons For The Modern Drummer DVD if you have any aspirations to become a drummer.
It contains pretty much everything you'll want to know about hand technique and more.
Things with strings:
Ibanez J.Custom, Prestiges, RG8, SR5 bass etc
LP's, Strat, Tele
ENGL Retro Tube 50
5150 III 50W
Orange Terror Bass
Take your Ipod and play along. Great technique is awesome, but doesn't have a point in itself. Just play!
go on youtube and begin researching "gospel chops", you may or may not like the style but there is a mountain of knowledge about groove in that style
Yeah as others have said, just plug in your iPod, put some headphones on, and play along. I do a Guns N Roses set daily on drums just to keep me fast and sharp, on top of just teaching myself new techniques from books or whatever. If i could afford it, id get a drum teacher, but if not just play. Seriously just play. Experiment with different beats, work on rhythms, fills etc you hear in songs, work them up from a slow pace (40-50bpm) if you find them real difficult, and keep gradually increasing the speed til you can play it much quicker.
Practicing to songs is pretty fun, But I would also recommend practicing snare drum rudiments.... in particular: single strokes, double strokes, flams, single paradiddles, and "buzz" strokes. Practice leading with both your left hand and your right hand.

Also (and this is completely optional), I would strongly recommend playing open handed, it will help strengthen your weak side and improve your coordination.