Widgets are set to invade MySpace. The developer-shy social network is finally opening up to third-party applications. Created in conjunction with Google’s OpenSocial initiative, the site’s developer platform will officially launch February 5, but eager widget-makers can sign up now.

MySpace may claim 137 million more members than Facebook, but when it comes to third-party applications, it has some major catch-up to do.

While MySpace bided its time waiting for Google to perfect OpenSocial, Facebook saw its traffic almost double in 2007, from about 12 million unique U.S. monthly visitors in January to 23 million in December. This jump in traffic has been pinned on the popularity of the nearly 15,000 applications that began spreading across the site after it launched its developer platform last May.

In December, Facebook also opened up its API for use on other social networks—essentially, beating OpenSocial to its purported punch.

These widgets, ranging from helpful birthday reminders to scam crushes, have caught the attention of VCs as well as bored office workers. Earlier this month, application developer Slide raised $50 million in institutional financing.

With money like that behind social networking applications, MySpace members can count on having thousands of timewasters to choose from soon.