Yes if you are planning on applying this fall/winter/spring for 2010 matriculation, you will need to not only study GMAT but do a LOT of other things:
1. Research which schools fit well with your goals/interests. Also which schools do you have realistic chances of getting accepted to?
2. What are all the application forms and deadlines
3. Write all the essays (probably the most time-consuming part)
4. Get recommendations from others
5. Do interviews
I'm sure there are plenty of other things, but the business school application process is very involved and GMAT is just one of many steps. Research this forum, buy a couple MBA books (e.g. Your MBA Game Plan and/or How to Get into the Top MBA Programs). Good luck!