I'm writing a story set in the pre-Clone Wars period (between TPM and AotC). I was wondering--are there any active Jedi training centers around, besides the temple on Coruscant?

I tried looking on the Wookiee, but I couldn't find anything. >_<

Is there a MindGames store or something similar near your place where they stock tabletop RPG books? The current Star Wars RPG Handbook and certain supplements will definitely have a galaxy map showing Jedi Temples at various periods and will the be the most up to date source foregoing somewhere like Wookipedia. The last publication series was either after Revenge of the Sith was released or possibly even since the Clone Wars was, and the good thing is they incorporate all EU canon into a workable, gameplay style Star Wars universe (so include hyperspace travel times, major trade routes, and a wide array of miscellaneous relevant information that is absolutely spectacular for fanfic writers, all canon or unaffected by canon).

Essentially most of the major Temples of EU will still be around but either disused or in the form of ruins. AFAIK Coruscant was the only "Jedi Temple" in use at the time but you see the whole trick about this sort of canon is that it is canon only by exclusion, they didn't need another temple for those two screenplays, so no mention of another one is made, but the writers would happily have dotted them wherever needed had it been pursuant to the story. The existence of other temples elsewhere in the galaxy is definitely not precluded by the screenplays, although they would probably be called something else like "Jedi Mission" ie., "Padawan, go to the Jedi Mission in the Sector and inform Master Blabla of the following."

This way you get to preserve the centralised theme of the Jedi Temple on Coruscant whilst still providing for the fact it is simply realistic, given hyperspace travel times that there would be Jedi outposts in the outlying regions of the galaxy for resupply and safety, a port of call if you will, possibly automated.

Another thing to consider here is the extensive and highly developed nature of Jedi powers in the RPG series. Jedi don't need astrogation computers for example, although it is preferred to have an astrogation droid as it also serves as a crewmember and vehicle maintenance support. There is a power many Jedi learn to plot complicated hyperspace routes in their mind using the Force, the way it works in gameplay is they always get the "expert" result in navigation rolls and may navigate without a working astrogation computer installed. Jedi navigating in this fashion get to ignore penalties for unusual or infrequently travelled hyperspace routes, so a journey which might take a civilian liner a month to partake would take a Jedi perhaps 3 days piloting the same vessel if he navigated using the Force, and there is no chance of catastrophic navigational failure (such as plotting a course which accidentally passes too close to a supernova).

So essentially, according to RP dogma the Jedi went galvantic around the galaxy in small starships with few consumables within days where regular folk had to take a medium sized transport with life support for a couple of months to make the same journeys. The galaxy was a much smaller place for Jedi because of this, so replenishment outposts were not as important for them as it would be for regular travellers. And mannned Jedi Temples then would only need to be in a region where a constant Jedi presence was required.