• Tesco Mobile Free SIMs and up to £40 Free Credit
Request your free PAYG Tesco Mobile SIM card. When you top up by £10, they give £10 free credit on top! A £15 top up gets you £30 free credit, and a £20 top up gets you a whopping £40 free credit! Free credit can be used for calls and texts to UK mobiles and standard fixed lines starting 01, 02 and 03, and can also be used for picture messaging and mobile internet browsing. They share O2's network with the same 99% coverage, and you can keep your existing mobile number if you wish.
• £100 Free for Switching your Current Account

Santander will pay you a whopping £100 if you open a Current Account online and move your banking using their dedicated Switching Service. You also get a 0% interest free Arranged Overdraft for the first 4 months, then 19.9% EAR typical (variable). Plus you'll earn an impressive 5% AER (fixed) for the first 12 months, on balances up to £2,500. That's up to £125 interest in your first year which means you'll earn up to £225 just for moving to Santander. To qualify for these rates a minimum of a £1,000 a month needs to be credited to the account, or standard rates apply.
• Free T-Mobile SIM Cards: Free International Calls and Cheap Internet
Fill in the simple form to request up to 2 free T-Mobile Pay As You Go SIM cards. If you top up £10 during the week you get £10 free credit to use that weekend on international calls or texts. Plus, when you top up £10 in a month, you get unlimited free texts for the whole of the next month. Also, get mobile internet with no nasty surprises. On any day that you use the internet it will only cost you a maximum of £1. No need to remember to buy a "voucher", the charges just stop going up at £1 :)
• Two Free O2 SIM Cards, Unlimited Texts for £5
Request up to two free O2 Simplicity PAYG SIM cards. With Simplicity, you can get unlimited UK Texts for a month for just £5. So if you top up by £10, £5 is deducted for Unlimited UK Texts, leaving you £5 of credit for calls, Bolt Ons, etc. If you text a lot and only make the occasional short call, this is the SIM for you.
• Your own unique Twitter SMS number for free
"aql.com provides a free and easy way to update your Twitter account via text message. Simply sign up for a Twitter number ... and we will assign an aql number linked to your personal Twitter account. All you will need to do is send a text message to the number and it will update your Twitter feed automatically!"
SendSMSnow lets you send free SMS text messages to many international countries and you receive text replies in your SendSMSnow inbox. You can also see a history of your sent messages.
• Free International Text Messages
Send free messages to any Mobile Phone internationally with Gizmo SMS.
• Free Nokia Unlock Code Generator
nokiafree.org have a free online Nokia Dct4/Dct3 unlock code generator for Nokia phones on various networks worldwide including all the major UK networks. The site also hosts a large "Nokia Flash Reverse Electronic Engineering" forum with around 250,000 members.
Send text messages to the UK free online or from your own mobile, no need to register. Even gives you an online delivery confirmation. Thanks to Josef Curry for this one.
• Free 30 days trial Fax to Email Service
PumaOne gives you a free 30 days trial of 0871 personal fax number which immediately forwards faxes to you as an email attachment. You pay nothing to receive faxes, and people faxing you only pay 8.5p/min to their telephone provider. You can also have a free voicemail number, also 0871.
Free BT Ringtones online guide.
Completely free polyphonic ringtones for mobile phones. You can download tones directly to your phone using WAP or upload them from your PC to your phone using a cable, bluetooth or infared link. Thanks to Thomas Jackson for this one.