Remember how awesome it was to have a Blackberry and be part of a BBM chat room? GroupMe is an app for iPhone and Android users that allow them to chat in a room with however many people they choose to invite.
One of the best features about this app is that anyone can join in the chat, regardless of what phone or carrier they are using. A chat room may consist of an iPhone 3G, a Motorola Razor, a Blackberry Pearl, and an LG ally without any issues.
The app has a clean user interface similar to any other chat application, listing contacts, current chats, invites, featured topics, and news. They will also be able to share pictures for all participants to view.
This app has a feature which allows the user to switch to SMS mode, which will take all of the messages in the conversation and send it to your native SMS client. This is standard for non-smart phone users, as they will receive every chat message via text.
I've been using GroupMe for a couple weeks now, and it is pretty awesome to chat with all my friends in one place!