All Headlines from September 2009 by Date
Vodafone are offering 3G dongles with no pay monthly fee and no expiry on download credits purchased. See here for details.
As far as I know they are the only company currently offering this, although if anyone knows otherwise I would be very interested.
Basically you buy the dongle for £39 with a gigabyte of credit for free, then when it runs out you buy another gig for £15. There no requirement to do this and there's no expiry on the 1GB you have purchased (unlike all other offerings I have seen). £15 per gig isn't very cheap admittedly but at least you don't have to pay it every month!