i have an old pc that i never use.. so i thought why not just use it for storage on my network.

what would be the best way to set this up? do i need any special software? i would be using a mac and a pc to access it

From the sounds of things, you have not fuddled about with Network Attached Storage (NAS) before, or much with PCs.

Step one, do some reading. There's little point in diving into something blind and you lose stuff stored on the PC and don't know why or how to correct it. Find out what specs are inside and their limitations. Then read some more. The more informed you are, the better prepared you will be if you need to spend money.

Google is your friend. There are tons of forums and threads and blogs and diatribe out there over how people have done this. Read about their experiences and learn from them. Ask questions if the posted info seems fresh (aka 1 week or so).

Step two, think about how much disk space you want it to provide and the goals. Is this just for storing critical documents or is it for music and media? Will you be backing up data or just using it to store stuff?

Step three, how much money do you want to sink into the project? If the drive inside doesn't have much in the way of overall space, you may want to consider options such as a second drive, or upgrading the one inside completely.

Step four, think about whether or not you want to tinker a lot or a little. If tinkering and investing in a lot of time isn't feasible, then try to follow the K.I.S.S. method ( Keep It Simple, Sane). If you ARE able to or willing to, then there are solutions right up your alley.

Step five, time to start planning. Once you have an idea of what direction you wanna go, see if your hardware supports that direction. One of your needs is to have multi-platform support. Thus, you should look for software that can handle both ( aka linux).

You can get very complicated and install a flavour of linux and the necessary services. You can also seek out made distributions, such as FreeNAS. Or you can simply install an old copy of Win2K and tweak it to share space via P2P. Again, it all depends on your willingness to invest time into it.

I'm not trying to scare you off, but it never hurts to walk in with eyes wide open.

I have to agree with "blueeyesm", this is not something to take lightly. If you want a safe, secure, and dependable storage system, you need to do your homework.

Will the system be up all the time?
Do you need fast access?
How much do you want to spend?
Do you want RAID?
Does the older system have SATA? (This will speed up through=put on the drives to the network).
Do you want to back up your PC's to the NAS?

Lots of questions.....:> )