Signage for a T-Mobile store is pictured in downtown Los Angeles, California
Signage for a T-Mobile store is pictured in downtown Los Angeles, California August 31, 2011. The Obama administration on Wednesday fired a legal broadside to block AT&T Inc's $39 billion acquisition of T-Mobile, launching its biggest challenge yet to a takeover and dealing the carrier a potentially costly blow.

T-Mobile and Wal-Mart have teamed up to offer a phone plan with unlimited internet and texts for just $30 per month, making it ideal for users who prefer to type rather than chat.

For $30 a month customers will get 100 minutes of calls, unlimited text messages and, importantly, unlimited internet usage. Aimed squarely at those who are alienated by the very thought of conducting a phone call, the plan will suit those who communicate through tweets ad Facebook status updates.

But, as the saying goes, if something's too good to be true, then it probably is. The plan allows 5GB of data in a month, and then the connection is slowed down until the following month, a process known as 'throttling'. When a user' service is throttled the internet is still available, but download speeds are restricted in an attempt to stop users from data-heavy functions, such as streaming films and television.

The offering of unlimited internet - albeit throttled after 5GB - was announced on the same day that Vodafone began a scheme offering trully unlimited internet to new customer in the UK for three months. Maybe with the influx of smartphone sales over recent years the carriers are now starting to realise that just a handful of GB per month isn't enough for some users.

The partnership between T-Mobile and Wal-Mart will benefit both parties; Wal-Mart can use the new plan to expand on its wireless product line-up; and T-Mobile improves its relationship with a major retail partner, after losing out with RadioShack.

T-Mobile will offer six handsets at 2,200 Wal-Mart stores, including its first prepaid '4G' handset; it's worth noting that T-Mobile's idea of 4G is actually a speed boost to the current 3G network, although in some areas it's almost comparable to Sprint's 4G WiMax product, according to CNET.

The $30 plan with unlimited internet will be available from October 16, just in time for anyone who's looking at buying an iPhone 5 contract-free, which is tipped to be available from October 21.