I need a 10 minute timer in the form of minutes:seconds:milliseconds. Before going about it the LONG way (creating every frame), is there a generator or anything I can use that I'm missing?

I use a program called XNote Stopwatch
I then set the colours of the backgrounds and numerics for easy chromakeyiing, I set my timer countdown and run camtasia studio. I capture the video and then reimport that (i use Vegas)
This is then overlaid on the video track, and resized with pan and crop positioning. If i want it to be pretier, u can also use an animated lower third to "frame" the timer

XNote Stopwatch? I've never heard of it... I'm running this on a mac. Compatible?

not sure, u might need to check that

So the question still stands... AE timer available?

It's not milliseconds, but you could use the timecode feature (under video effects) which generates timecode and displays it in hh:mm:ss:ff on the image. Apply it to a layer, pre-compose it, then retime the precomp layer to -100% (reversing it). Mask out the parts you don't want.

Sure, the numbers in the last area only go up to 24/25/30, but they go by quickly enough. You could even use cc force motion blur to make the frame numbers looks blurry.

good call, thanks. That's what i was looking for