Wow! Is that 300 texts a month forever? Do you have to topup with £10 every month? (I ordered 4 anyway!)
I got the Tmobile ones last month, with 2000 free texts over 3 months, for the DSs; when those run out they can use these . The DDs both have contracts but usually go over their text allowance; DD1 said she was planning to buy a really cheap phone to use on PAYG so she can have one too. (We are drowning in mobile phones in this house!)
The free SIM card offer ran out, popsy, but their website says you can still do it if you buy a phone and the Nokia 3410 (which is the one I have - "you wouldn't understand dear, it's called style"!) is only £19.99.
If the 2000 texts only last for 3 months it's not really worth it though; the 300 texts a month from O2 is probably better if it does go on indefinitely.
No catch.... i got 3 last time they did this offer and because i was already on O2 payg, I could register the new sim, tell them i was an exister and they cancelled the new number and put £5 credit onto my original sim!
Popsycal - yes - tell your current provider that you are swapping to a new one and ask for a PAC. They'll give it to you, along with a use-by date. Contact the new provider and tell them the PAC. They'll give you a date of change (possibly a week away). In the meantime, you'll continue to be served by your old provider. All the time that you are talking to these people, have available the phone number, the sim number and (I think - not 100% sure) the serial number inside the phone battery compartment.