i would try a few things.
white noise, night light, and a few nite time board books in bed with him. my son was waking at this odd hour too during the same period in his life, though sometimes he would try to talk to us when we laid him down in our bed, we would mostly ignore it and go back to sleep, and whether or not he did immediatly go to sleep, or eventually, we were all sleeping within 10-15 minutes i would say...
just dont respond at all to his attempts at playing.
also, if its possible to have his bed in your room ? you could try that for a while. our son seemed to take comfort in the fact that we were right there. and he doenst have to get very upset before we get to him either.
i dont know.. try some white noise. and experient with different kinds. classical music, fans, static on the radio, theres a cd out there called 'for crying out loud' that has 8 tracks of different white noises on it. its awesome. our son had to have the vacuum running for the first 2 months then we found this cd which has a vacuum track on it! :D it was too late to save our vacuum, but good enough to save our sleep! however, that was when he was just a baby.
but put some things in his bed with him so maybe he could read some books or something when he wakes up. some kids (like my son recently) just end up throwing those things around, so make sure there isnt anything breakable within throwing distance.. even try putting toys in bed. i dont know.
i think that in a month or 2 htis will change again. maybe there are some molars coming in. try some teething pain remedy - tylenol, etc..
check the temp in his room, any clothing discomforts, listen for any wierd noises (which wont matter if you do white noise), use a night light ... soft music? hmm...
check www.askdrsears.com for more info on sleep...