I discovered that the pins that the front calipers slide on were really stiff. I took them out and cleaned them and now I wonder what kind of lube to put on them, if any.

Use the disc brake grease. Comes in the little squeeze packets at the parts store.

i use white lithuim grease!

http://www.permatex.com/products/Automotive/lubricants/specialty_lubricants/auto_Permatex_Ultra_Disc_Brake_Caliper_Lube_1.htm This is the right tool for the job.

Thanks for the tips! I used some of this http://www.powerupusa.net/info_rcl1000.htm because I had some handy. If they seize up again I'll use what you guys have recommended.