Color correction is 2-fold.
1. Pre-process as analog before capture, meaning proc amp, as needed. And the PA-100 is a nice proc amp. There is a Sima that I also sometimes like to use (forget model offhand, would have to dig it out later), but it differs from the PA-100. I've been known to chain both.
2. Post-capture process in software. VirtualDub
Colormill sort of works, it can be hit-or-miss, not always the easiest for color correction. NLEs tend to be best, and I've used Adobe Premiere quite a bit in the past, as it really does mimic Photoshop to a degree. Avisynth is a terrible general color-correction tool (horrible UI, not friendly at all, even with AvsPmod), but it can be exceptional for tricky corrections. DaVinci is becoming a favorite for some folks, but it has limitations on files (ie compressed files, not uncompressed, a deal breaker for many of us).
Color correction isn't a hard skill, but is mostly (A) how well the source cooperates to make the desired changes, and (B) having the right software and/or hardware.
Also required = calibrated monitor, so you're not "correcting" the values to a bad monitor.
And lots of patience. This task is tedious.