well, I just got back from the DMV - it was painless, yet reminded me why I hate driving.

Anyhow - Track racing is the best. I worked with some pretty dedicated trackies while living in Colorado Springs. I think I saw isotopesope out there on training wheels in 97.
I literally just bought my nightly license and insurance and then took down the field when I hit the banks too slow. HAHA!
The easiest thing is to go to the nearest track (or check the website) for info on clinics for beginners and look for CAT5 race night (you will start out at CAT5 and I highly recommend you take your time upgrading - there are a lot of rookie CAT4s that might as well race drunk). Race a few nights as a CAT5 and go to clinics until you have your bike handling skills sharpened to the point where a big CAT4 group is manageable.
Here in Chicago, they have to split up the CAT4 group into halves as it is so big. Personally, I think that there are a few 4s that should hang back with the 5s. Two clinics and one night of racing does not a 4 make. It is not about upgrading ASAP - it is about safety and then speed.
Enjoy!