O2 has announced that from the start of August, every O2 customer will be able to switch on text notifications within Twitter and receive replies and direct messages completely free. You'll also be able to send updates to Twitter as part of your normal text message bundle, rather than them costing extra.

"We believe that mobile will soon become the most popular way of accessing social networking sites, giving real time access to tweets and status updates wherever you are" said Antony Douglas, head of content at O2

Twitter stopped offering phone updates about a year ago in the UK after it was revealed that it was costing the company a fortune. At the time, it was costing Twitter $1000 per user, per year to send SMS outside of Canada, India, or the US.

In March, Vodafone announced that it had done a deal with the company to bring them back. Vodafone's texts come out of your bundle however, whereas O2 seems to be indicating that it's going to send you messages free.

However, many customers have switched to Twitter applications on their phones instead, like Twitterfon, Gravity and Twitdroid, which take advantage of handsets' data packages.