Pay your self first is a primary axiom of contemporay personal finance.
Also traditional/roth 401(k)s, traditonal/roth IRAs (great tax shelters, look into their respective pluses/minuses). Can't go wrong with either as you will take advantage of compund interest, and if you invest on schedule, DCA (dollar cost averaging).
Invest in index funds with low expense fees (make sure no loads, no 12-b1's, etc.). Stay away from individual stocks, plenty of research indicates individuals, on average, who invest in the market directly through individual equity and debt securities will have returns substantially lower than the market itself as a whole.
For some great reading from blogs I suggest:
Get Rich Slowly
I will teach you how to be rich (Former classmate at Stanford)
PFBlog
For a free online course (UC Irvine) check out the following link:
http://ocw.uci.edu/courses/AR0102092/