3G Dongles

[bloodhunter]

I am thinking of getting a 3G dongle to use on my laptop in areas where wifi is not available.
I would be getting a pay as you go as i dont want a contract but are there any of the networks offering one that does not expire after a month or whatever.
In other words i want one that will carry on working untill the credit runs out, a bit like my mobile phone which still has about £8.00 credit remaining from a £10.00 top up 6 months ago.

Thanks.

 

[ANDARIAL]

Not anymore Vodafone used to do one(strokes his unlimited time sim )
Three sims can be got cheap,around £9 for 3gig,lasts 90 days from the bay