MySpace Mobile is adding a new dimension tonight—streaming video, both user-generated and branded, to the phone. Caveats: it’s in beta, and requires logging into a MySpace profile, but will work with the “most popular streaming-enabled mobile devices,” like the BlackBerry Bold, Palm (NSDQ: PALM) Centro, Motorola (NYSE: MOT) Q9, LG (SEO: 066570) Voyager, Nokia (NYSE: NOK) N95 and Samsung Instinct. The Fox Interactive Media (NYSE: NWS) unit says the streaming capability will be rolled out globally using RipCode’s transcoding technology, allowing it to supply multiple handsets without having to create video specifically for each one or to store multiple formats.

—No iPhone: A few names are missing from that supported list, including the iPhone. Why? MySpace opted for real-time transcoding rather than progressive downloading, which is what the iPhone supports. MySpace says this option allows it to reach “a wide community of subscribers.” (It also allows live streaming, which could come in handy.) From a fact sheet distributed to the press: “Based on research from industry analysts, the majority of the mobile community has streaming-enabled devices, especially in the U.S. market. This is supported by MySpace’s own mobile web site traffic analysis.” 

—Content: MySpace says all user-gen video and most branded content, including TMZ, the NHL, National Geographic, The Onion, and College Humor, should be available.

—How it works: Wish I could tell you from experience but MySpace appears to have sent my log in to time out. This video should help:

My Videos on MySpace Mobile website