groove3, Lynda, MacbookPro Video, etc..
they'll all have in depth mixing courses, mastering, etc.. everything.
I use groove3, 15 bucks a month. More than worth it. Once I'm finished with groove3 I'm gonna move on to lynda. But Groove3 is perfect for a beginner I think.
Honestly, i wouldn't worry to much about what DAW they are working in, mixing techniques are not restricted to DAWS, basic EQ, Compression, Panning, and Levels will go really far with a mix. Just use the techniques you learn within the daw and plugins you have. Cutting at 250K is cutting at 250 no matter the DAW just like 4:1 compression is the same in all DAWS.