Fifth placed handset vendor Sony Ericsson looked hopeful this week, refreshing its handset portfolio and getting in on the services game with an unlimited music offering.

The Japanese-Swedish joint venture has been on the back foot this year, having been overtaken by Korean rival LG, and losing market share to stronger competitor portfolios.

Despite the strength of its Cyber-shot and Walkman brands, and a solid array of feature phones, Sony Ericsson has to date lacked the kind of services play being championed by Nokia and Apple.

But that has changed with Wednesday’s introduction of PlayNow plus, an all you can eat music download service, which will launch in the fourth quarter. Telenor Sweden has already signed up to the platform and a special edition of the W902 Walkman phone will be the first product released with the integrated PlayNow plus service.

Based on the existing PlayNow music store, the plus service draws from Sony Ericsson’s collaboration with Omnifone and, “guarantees truly unlimited, ‘all-you-can-eat’ access to millions of music tracks.” There’s also a social aspect, with subscribers able to recommend their music tastes to others in the community. And even after their contract expires they will get to keep “a number of tracks” (their most played favourites it says here) DRM-free, which is kind of a compromise to the usual stance.

Music labels EMI, Sony BMG, Universal Music Group, and Warner Music have already agreed to the deal.

Sony Ericsson revised the PlayNow store late last year, allowing consumers access to a greatly expanded range of content, discoverable through features such as TrackID, which allows users to search for songs using snippets of lyrics, as well as over the air downloads to the phone or side loading of content from PC to mobile.