The microsot website posted a Video Tuorial series on Vlookup for Excel. I strongly recommend you check it out:
http://office.microsoft.com/en-us/excel-help/overview-RZ101862716.aspx?section=1
Also be sure to download the VLOOKUP Quick Reference Guide:
http://office.microsoft.com/en-us/excel-help/redir/AF101984660.aspx?CTT=5&origin=HA101873816