Firewire is also known as IEEE 1394 and if you have it it will be shown in Device Manager. It is a very fast way of downloading video from a camcorder. Adding a Firewire card to a PC is very simple if you have a spare PCI slot on your motherboard. Most will install there own driver, but if your OS is an early version of XP you might need a driver disc or need to download a driver from the internet.

Does you Sony Camcorder have the type of connectors shown in woodchip's USB adapter? Some do some don't. But most recent Sony's have Firewire, which they sometimes call iLink.

What output sockets as it got on the camcorder

Yes the Sony that you linked to would give you better quality footage, but if you are considering a new HD camera then take a look at these reviews. Before you choose think about how you will use the camera and what is most important to you, for example the miniDV type that you have now gives you automatic backup even after you have downloaded its contents onto your PC, the tapes are cheap and easily stored. Hard drives in camcorders are just the same as in a pc, they use moving parts, can crash, when full they are written over so your originals are lost. Camcorders using SD cards are again easy to archive, no moving parts, SD cards are cheap to buy. Personally I have a Sony miniDV HD camcorder and will use it until it falls apart, I like the simplicity of it and have no complaints about its quality - but then I am not a film maker, just a recorder of family life.