You go onto the virgin network, I think the deal expires at the end of March (will prob be replaced by another one) You can keep your number. They send you a free sim card and you pay £10 per month and get 300 xnetwork mins and 300 txts, they both rollover unused as well. My missus, brother and a few mates are on it now and can't fault it. The other good thing is that its a 1 month contract! If you don't like it give them 1 months notice and they will cancel.
heres some info from the
virgin site:
†Virgin Mobile offer
New and existing customers (subject to status and credit checks) are able to get the Virgin £10 with Cable tariff 300 mins/ 300 texts ("Promotional Tariff"). As part of this you will also get the SIM for free (normal price £10).
You must pay the Promotional Tariff by Direct Debit.
Virgin Mobile services are subject to credit check. Offer valid when connecting to the Virgin Mobile network. Offer ends 31.12.06.
If you cease to be an customer for any reason, you will no longer be eligible for the Promotional Tariff and your Virgin Mobile tariff will revert to the standard Virgin £20 talk SIM only (300 mins/300 texts), effective the month after termination.
You may however change or terminate your Virgin Mobile bundle in accordance with the Virgin Mobile "Legal Stuff" for Pay Monthly SIM-only Bundles.
Hope this helps.