Thanks Steve and Cobbydaler for your help and advice with this.
So clearly the Linksys Wireless-G Broadband Router WRT54G is the favourite amongst you. I am intrigued that it gets such a hearty recommendation. I don't know why - maybe ease of installation and use? - but I am happy to go with that rather than the Belkin model, especially as Dabs, the company I am buying the laptop from, also stock the recommended model for £46.60, so I can order both at the same time.
Anyway, thanks again for your help. It is very much appreciated.