These apps are available with a streamlined web interface, where you can easily bookmark a single web address and seamlessly switch between applications. Bookmark http://www.google.com/m/a/example.com from your iPhone's browser, but remember to replace "example.com" with your actual domain name.

Alternatively, you can connect to your iPhone's Mail application to Gmail using IMAP for free. Learn more here and here about how to configure the iPhone's Mail application to do this.

Google Talk

You can instant message from your iPhone with Google Talk, too. Bookmark http://talkgadget.google.com/a/example.com/talkgadget/m from your iPhone's browser, but remember to replace "example.com" with your actual domain name.