That's why I'm a big fan of IMAP. It keeps all my Gmail in sync wherever I go and on whatever computer or device I use to access it. You can from Google's help pages.
Ready to give it a try? Here's how:
1. Log in to your Gmail account, then click the Settings link at the top.
2. Click the Forwarding and POP/IMAP link, select Enable IMAP, and then click Save Changes.
3. Click the Configuration Instructions link to learn how to set up your e-mail client to access Gmail via IMAP. (You'll need to make a couple small changes if it's already configured for POP.)