Drawing is the fundamental skill for pretty much all art. If you're looking at colleges, find one that offers good classes in Observational Drawing, Figure Drawing and Anatomy. Make sure the class does a lot of professor and peer critiques.
Even if the school doesn't have a class specifically for game art, if you have a strong foundation in the fundamentals, you'll be able to figure out the rest on your own/online/making a game with friends.
While you don't want online courses to replace college, they are an excellent way to expand your skills in addition to college granted that you can manage your time.
For example, CGSociety has a 3 week course in rapid game character creation starting October 29th. http://beta.workshops.cgsociety.org/
. They have a variety of great courses taught by industry experts. I haven't personally been able to take advantage of these yet, but I do drool over them.
A digital tutors subscription http://www.digitaltutors.com/11/index.php
is worth the money. They break their tutorials up into 15 minute or less chunks so they're thorough and easy to follow. 3d Buzz is another recommended paid tutorial site.
Gnomon Workshop http://www.thegnomonworkshop.com/
has excellent online courses/DVDs
YouTube videos created by professionals are a free way to learn more. Example: Jason Chan's concept art tutorials http://www.youtube.com/watch?v=1no3IVKnOmM
Posting your work on forums like this, cgsociety.org and game-artist.net is a good way to get feedback. Some even have competitions you can enter for extra motivation.