Not the first by a long chalk ...
I seem to remember CPW have taken this road before - and long before O2 in 2003. A company called Jingo launched the first mobile content portal - albeit an online offering together with a gateway service - way back in 1999. They got into bed with CPW and were unceremoniously shafted as I recall.
Here's what you said at the time - http://www.theregister.co.uk/2000/02/09/geldof_and_moore_plug_wapworld/. There's a wiki here too - http://en.wikipedia.org/wiki/WapWorld.
Plus ca change ....