A report from M:Metrics indicates that mobile social networks are growing worldwide, with MySpace taking the biggest chunk of mobile users in the US and the UK.

In the US and Western Europe, M:Metrics is reporting 12.3 million consumers accessing a social network via their mobile phones for the month of June. The US had the largest number of users, topping off at 7.5 million mobile subscribers. Italy is next, with 1.3 million, then the UK with 1.1 million, and then Spain, Germany and France. The most visited mobile networks for the US and the UK were MySpace and Facebook, with Bebo also garnering significant users in the UK, and YouTube coming in third for the US. MSN was the most popular network for the mobile users in all the other countries considered.

If you’re wondering about the wireless service providers, M:Metrics notes that Amp’d, AT&T, Helio and Nextel users were the biggest group to sign onto MySpace, and Sprint, AT&T, Virgin and Amp’d were the providers most used for Facebook access. YouTube was most used on Verizon. These additional stats are interesting and useful to have, considering the many initiatives wireless providers are pushing in order to provide access to social networks, as well as trying to hone in on the influence of a particular cell phone (iPhone) or wireless service.

There are also cell phone makers that are creating networks themselves, like Nokia, and the social networks are also looking to push mobile access as well. Looking back at these numbers and comparing them with additional stats over time will offer insight to the growth of the mobile network sector.