For now you can only use DPP (Canon Digital Photo Professional) which is a great software anyway.
Adobe has not released yet an upgrade to Camera RAW that includes support for 50D and 5D Mark II.
Support for the 50D will come soon as a beta version is already available at Adobe Labs. I don't know if you can download it yet, I was a betatester for Lightroom so they gave me access. In any case the link is here:http://labs.adobe.com/wiki/index.php/Camera_Raw_4.6
I tested it a bit and it seems to work fine, Lightroom 2.1 Release Candidate is also here.
I grabbed my 50D Thursday evening, I'm going out to shoot today.