AOL (NYSE: AOL) is the latest company to woo mobile developers by offering them tools to make it easier to get their applications on handsets. The company announced plans today for an “Open Mobile Platform,” that will give developers tools and source code to build and distribute applications on platforms, including BREW, Java, Linux, RIM (NSDQ: RIMM), Symbian, and Windows Mobile. The platform is expected to be available this summer

AOL said it will be based on an XML-based, next-generation markup language; an ultra-lightweight mobile device client; and an application server. In addition, developers will be able to tap into such AOL properties as AIM, AOL Mail, AOL Video, MapQuest and others, and integrate banner ads into their applications. Release.

AOL’s entrance in offering a platform will create further fragmentation in the industry, however, AOL is no slouch in mobile. In the U.S. for the three months ended December, it had the second most popular mobile IM client after Yahoo! (NSDQ: YHOO), and ranked fourth in mobile email, according to M:Metrics.