O2 UK has announced that it's enabled a 900MHz 3G network in London, Manchester, Leeds and Birmingham, after the carrier obtained permission to use the spectrum from communications regulator Ofcom in January. O2 says this will increase its 3G coverage, improve download speeds by 30% and network capacity by 50% in these areas.

To take advantage of O2's "3G900" service in the cities with coverage, you'll need a phone with UMTS/HSPA 900MHz capability. Thankfully most popular Android smartphones sold by O2 fall into this category. The Xperia X10, HTC Legend, Wildfire and Desire series, as well as the Samsung Galaxy S series should all be able to use O2's speedy new network.

O2 says it will use a range of new technologies in the future to improve its mobile data network. Nigel Purdy, O2 UK's CTO, mentions in today's press release that the carrier plans to implement HSPA+ and LTE networks in addition to its current 2G and 3G coverage. [O2 UK]