I have found that I am increasingly relying on Google Talk to get things done quickly. It is like I have been thrust right back into my days with AIM (8th grade was a big year for me in that regard). I just wanted a way to only have Google Talk as an application for Google Apps. Google has an application for Windows, but I am using a single site browser in order to do it on a Mac.
Step 1: Download Fluid
Step 2: Create an application with the following URL (making sure to replace YOURDOMAIN with your domain): http://hostedtalkgadget.google.com/a/YOURDOMAIN/talkgadget/client
Viola! You have an Google Talk Application that connects specifically to your domain.