Stu Maschwitz explains the features of Two Free Color Correction Plug-ins from Red Giant Software. There's also info at Red Giant:
“Magic Bullet Colorista Free is a simplified, elegant color corrector that anyone can share and use. Our popular 3-Way wheels and RGB numeric sliders give everything you need for basic color grading, and it is workflow-ready for sharing industry standard CDL data.
Magic Bullet LUT Buddy was designed for the professional colorist and bridges the gap from desktop applications to high end systems and hardware boxes. Use Magic Bullet LUT Buddy with apps like After Effects and FCP to output LUTs and communicate with higher end systems ranging from DaVinci Resolve to Panasonic displays. If you're already using 1D or 3D LUT's in your workflow, this tool was designed for you to share values between compliant software and devices.”
Colorista Free works with Adobe After Effects CS3, CS4 and CS5, Adobe Premiere Pro CS5 and Final Cut Pro 6 and 7. No Avid, since AVX won't support the color wheel UI.
Magic Bullet LUT Buddy works with Adobe After Effects CS3, CS4 and CS5, Adobe Premiere Pro CS5, Final Cut Pro 6 and 7, and Motion 3 and 4.
There's plenty of information on this older-style version of Colorista; see for example, Short primer video on Colorista and color correction and Colorista mini tips from 5tu.