Google Talk for Mobile Phones

I'm sure Google is working on this feature, but until they get this done, there's an open-source project that may help you. MGTalk is a Java midlet that lets you connect to any Jabber server, supports SSL connection, has a basic chat history and a Gmail notifier.

And if that client doesn't work for your mobile phone, you may try this modified version that works on any HTTP enabled network.

Before entering your Google credentials, remember this is a third-party application. As MGTalk is open-source, you can always check the code to make sure your password is safe and even recompile it.