Any advice on dongles what are prices like spec etc, and could the day come when they replace routers?

Dongle is a catch all term for any USB pen drive. If your talking about a wireless USB reciever for your PC, then you'd be looking at around £29.99 for a netgear model.

I was thinking about getting one instead of installing a land line in my new flat. The landline wouldn't be needed as anyone phones my mobile anyway. I am currently on Orange and for £15 a month you only get a 3GB download limit, and for every gig you go over they charge you another £15! So if you are going to get one make sure you are fully aware of all charges before agreeing to an 18 month contract.

Actually dongle has been used for anything small needed to plug into a computer for years, well before even usb came around.