The critical moment came this afternoon when Richard G4WFR tweeted that he'd been having some fun over the weekend with one of the sticks. I quickly asked him which USB stick he'd used, which he told me was a Newsky TV DVB stick (eBay number 110898287043). The critical thing is that the USB stick must have the RTL2832U chip & E4000 tuner in it. Managed to order one of those sticks for £13 including postage, so I'm looking forward to it arriving.
Richard is using the SDRSharp (SDR#) software which can be downloaded at http://www.sdrsharp.com/index.php/downloads - although I think I have seen people using other software. Richard mentions that a special driver for the USB stick is required, which can be downloaded from this site, rather than the supplier USB driver.
Richard mentions that he is getting coverage between about 60MHz and 1.7GHz with useful sensitivity. If I can do the same, I'll be happy. Once it arrives, I'll have a go at hooking it up and see what mischief I can get up to with it.
Richard G4WFR has just put together some notes on his experiments so far, which look very useful