This simple workaround may help if you maintain two different Google Accounts and have to chat with Google Talk friends who are spread across both these accounts.
The desktop edition of Google Talk comes in two flavors – the standard client and the labs edition. The trick is that you can install both these clients along side each other and even run them simultaneously using different Google Accounts as in the screenshot.
Here I am running Google Talk standard desktop client using my Gmail login while I have logged into the GTalk Labs edition using my Google Apps login. Both clients run simultaneously on the desktop without any problems. If this fails to interest you, try the Digsby option.
Related: Is Google Talk Blocked