Networked hard drives

Looking to buy an external hard drive and network it if this is possible. My set up is:

Macbook 80GB hard drive running Tiger
iMac G5 250GB hard drive running Panther
Wireless network via a Netgear DG384D router/modem
Airport Express Base Station connected into the TV/Surround sound unit used for streaming iTunes

Ideally the hard drive would sit somewhere on the network (plugged into the Express or the router) and be acessible to anything on the network.

I know about the Airport Extreme with the USB connection for a hard drive but don't particularly want to blow £120 on one when my router works fine as it is.

Anyone done this and got any recommendations for setup or hard drives? Looking for something with 250GB+ storage that's also portable enough to take on the road

Thanks in advance for any help

There are dozens of USB and Ethernet equiped external hard drive boxes in existance.

http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=487729

would do it. I have bought a number of Icybox products, they are cheap and reasonable quality.

You could check out

http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=273369

for a netgear alternative (I would however check their supported drives because apparently not all drives work with them)