Microsoft today launched an Android app, Tag, the first to be developed for the direct competitor to Microsoft's own mobile OS, Windows Mobile.

This isn't the first time Microsoft has developed for a competing handset. In fact, Tag has already launched on most other popular smartphone devices, including Windows phones, the iPhone, and Blackberry and Symbian devices. Microsoft also launched a Bing app for the iPhone, which lingers in the App Store at an unfair disadvantage to Google, the search engine that comes automatically embedded in the iPhone's default browser, Safari.

Nevertheless, Microsoft clearly cares more about spreading its applications to more users than about remaining stubbornly indifferent to its immediate competitors.

Tag lets Android owners use their device as a barcode scanner, effectively. The user takes a photo of a barcode and the program identifies it, possibly alerting the user to special coupons or discounts available for the item or at the store.

Curiously, Tag is not just competing with third-party applications like ShopSavvy, which functions similarly to Tag, but it is also going up directly against Google Shopper, a Google-designed app that lets you photograph items, not just barcodes, to search for them.

Just a month ago, Microsoft unveiled Windows Phone Series 7, the latest version of Windows Mobile intended to compete directly with the iPhone OS and Android. The new OS will be launching publicly later this year.