Mobile 3G Internet
Yesterday I switched my mobile network provider to '3', mainly because of their attractive fixed-rate Internet bundle. For £5 I get 30 days Internet access, up to a 2GB data-transfer limit. Compare that to my previous network provider (who shall remain nameless) and my £5 would get me only 1MB (0.5p per KB). Obviously this has given me a lot of freedom to surf the web, send/receive email and read RSS feed, which are supported nicely on my Sony Ericsson K800i. Other networked applications I have installed so far are Google Maps and YouTube. I had always wanted to use Google Maps when out and about before, but the amount of data that it uses was just too expensive before.
A particular feature that I have found interesting is my phone's support for IMAP4 'push' email. After adding support into my Courier-IMAP server, the phone receives email notification (like receiving an SMS message) as soon as new emails are stored on the server. If only my desktop mail client (Evolution) supported this too!
The other thing I want to mention is mobile TV. For £2 I decided to try out 3's 30 day mobile TV add-on. Quality is obviously not brilliant as it is streamed and there's not a mass of channels, but it's amazing none-the-less the first time you see it. I don't know yet whether I will continue to purchase this add-on, but I can see it being a boredom-buster for those train and bus journeys.
Overall, I'm really happy with the switch--SIM card cost nothing (free with £10 credit), it's given my phone so much more value, I'm getting to keep my old number and still on pay-as-you-go (pre-pay).