You contact the old employer by phone, email or snail mail -- or all three --to make sure they have your current address. Employers have until January 31 to issue your W-2's. You must enter ALL of your W-2's on the same tax return. So make the extra effort to get it.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**