How can I get Gmail Chat to run in background on my iPhone? For my iPhone, is there anyway to have gmail chat ping me, when a new chat occurs, and I am on another app?  Unlike Android or Blackberry, I am amazed that I have yet not found anything that works well on the iphone for chatting with friends.  Am I missing something here?  Or is this just one of the greatest overlooked features that my iPhone does not have.  

And any solution offered can be either from the app store or cydia.  Thanks.
Trillian for iPhone works great for this.  Supports push notifications and multiple other IM networks besides Google Chat.