Suddenly, MySpace has just become one of the largest application developers on the Facebook Platform.

Just a few minutes ago, MySpace announced that it has acquired iLike, developers of the largest music app on Facebook and one of the 15 largest application developers overall by total reach. iLike, as you may remember, famously exploded from zero to two million users in the first two weeks after the Platform launched in May of 2007.

With the acquisition by MySpace, we move to the next chapter in one of the more dramatic relationships between Facebook and an application developer since the Platform has been around. Facebook has long been exploring different ways it could get more involved in music, from working directly with the labels to building its own service to hiring an intermediary developer to manage its music efforts.

Obviously, any decision by Facebook would have a tremendous impact on iLike (and all other music application developers), and as Facebook explored those different options over the past couple years, relations with iLike apparently became increasingly strained.

In fact, iLike CEO Ali Partovi had some seemingly harsh words for Facebook yesterday, telling CNET in an interview, “Twitter and the iPhone are the platforms of the future.”

Facebook wouldn’t comment much on the MySpace acquisition of iLike today. When asked if the deal would affect anything for iLike going forward, a Facebook spokesperson responded:

“iLike was one of the first applications built on Facebook Platform and has become a success with more than 10 million monthly active users. We expect that users will continue to discover and share music through the iLike application on Facebook.”

For its part, MySpace says the acquisition is part of the company’s strategy to provide increasingly distributed services to artists and bands. In addition to being the largest music app developer on Facebook, iLike has also built popular music services on Bebo, Orkut, hi5, and iGoogle. Artists publish content to users of all iLike’s applications via a single “universal artist dashboard.”

Nevertheless, Facebook is still the place where iLike has built the biggest audience, and it will be interesting to see what MySpace does with its newfound access to millions of Facebook users. iLike has created a valuable platform for artists, brands, and advertisers – the company says it is profitable – but MySpace may have larger ambitions to increase its footprint within the Facebook ecosystem. On the other hand, MySpace may be more interested in integrating iLike’s discovery tools on MySpace itself, and/or extending them to other kinds of content as well, like movies or games.

Regardless, things will be interesting. However, it should be noted that MySpace is not the first business in a related space to have a popular application on Facebook. For example, LinkedIn’s Bumper Stickers application serves 5 million Facebook users per month. Nevertheless, it is clearly now the most directly competitive.