I HAVE FIVE Gmail accounts (sounds greedy, I know), so I've had lots of chances to encounter and overcome some of the Web mail service's hassles. Here are two essential Gmail tips I've picked up.

Use Gmail Manager for Multiple Gmail Accounts Checking multiple Gmail accounts is a pain, what with the signing in and signing out. That's why I rely on one of my all-time favorite Firefox extensions: Gmail Manager.

True to its name, the add-on lets you manage your various Gmail accounts from within your browser. After installing it and configuring your accounts in the Preferences, you'll see a Gmail Manager status bar in the bottom-right corner of the browser window. Mouse over it for a pop-up listing your newest messages. Click it to open Gmall in a new tab. Or right-click it to select a different account.

Gmail Manager has loads of options you can tweak, such as new-mail notifications, a numeric unread-mail count, and a pop-up "snippet" box. It does everything you could want short of actually reading your mail for you. This is a killer extension and a must have for anyone who uses more than one Gmail account.