If you are considering graduate study in philosophy, you need to have some idea of what will adequately prepare you for it. Because there are different styles of philosophy, your optimal undergraduate program may well be affected by what sort of philosophy you aim to pursue in your graduate work.
Here again the most important piece of advice is this: talk to members of the faculty about the kind of work you are interested in doing and get their advice about which graduate programs you should be thinking about and what kind of preparation they require. Faculty members are by far the best sources of this sort of information. Too many students fail to seek advice until it's too late to get the appropriate preparation and find themselves scrambling to fit the necessary courses into an already busy senior year. Even if you are not sure that you might want to do graduate work, seek out advice anyway. Students contemplating graduate work should also consider taking an honors degree at the undergraduate level.
The guide books you find in book stores will probably not be very helpful to you. Things change too quickly for them to remain in date. But you should consult the internet resources linked to the Tanner Library web site, particularly the Philosophical Gourmet Report. Each fall the Department has a meeting to discuss issues about graduate education with students who are considering making an application.