Please help me , in a spreadsheet working

I am working with two different spreadsheets. The only common field between the two is say "bill_no". Now say, in the first spread sheet there are certain information available in respect of each bill which is not appearing in the second spreadsheet. At present i am doing copying out the information from the first spread sheet and then going back to the second spread sheet finding out the bill no by Alt+F and then pasting it. This seem to be huge manual involvement. Some of my freind told me this can be done easily by using vlookup function. Can anybody please help me out? Please help me by telling the steps and the syntax.

thanks,

Alok