Apple has quietly released a 1.1.5 firmware upgrade for the iPod Touch. The 1.1.5 firmware remains a free upgrade path for firmware 1.1.4 users who chose not to upgrade to 2.0.

The 2.0 upgrade was released over the weekend and brings support for MobileMe, Exchange, 3rd Party Applications (App Store) and more. Based on early reports, firmware 1.1.5 appears to add no new features but may improve the speed and stability of existing applications. The update is available through iTunes.

Meanwhile, it appears that Apple is already testing version 2.0.1 of the iPhone and iPod Touch firmware.