It isn't really worth learning to use QBASIC nowadays, since very few people will program in that language. If you feel you have to try it, qbasic.com is a good starting point.

If you're feeling particulary masochistic, by all means try learning C first, however I'd advise against this course of action since I tried it and it's *very* difficult. Starting out in Perl, Python, PHP or any other interpreted language will probably be easier.