Foster City (CA) - The top voice-over IP messenger program on the Internet is now available for the PSP, as the first major feature for the portable system that is only compatible with the newer slim models.

Sony today released version 3.90 of the PSP’s firmware, with the only visible addition being a new tailored version of the Skype software. Users can download the application after updating their PSP.

There is a caveat, however. The PSP version of Skype is only compatible with the PSP-2000 model, otherwise known as the "slim and lite" PSP. Sony released the newer PSP last year, and unlike most console redesigns it actually has a few functional changes over the original.

For example, it has the ability to connect to a TV to allow big-screen playback of PSP content. The first version of the device does not have this functionality.

With a headset connected to the PSP, users can access all features of Skype, including text messaging, calling to other Skype users, and placing calls to regular phone numbers for a fee. The firmware update is available directly through the PSP as well as at Playstation.com.