I'm a bit puzzled by the bit about linking them with a crossover cable. You don't need to link the two machines together, just each machine to the hub (either wirelessly, or using ethernet cable (NOT crossover).
The next thing you need to do is ensure that they are both members of the same workgroup: Right-click My Computer, choose Properties, select Computer Name tab. If they are not both members of the same workgroup, on one of them click the Change button, and type in the name of the workgroup to match the other. You will need to restart the machine after changing the workgroup.
Next you need to set up the shares (i.e. choose which folders you want to share, and share them) For Example, open My computer, double-click the C drive, select a folder, right-click, select Sharing and Security.
Check the box "Share this folder on the network" (If you never shared anything before, you'll probably get a security warning. Answer that you understand the risks and want to go ahead) Decide whether you want to be able to change files in this folder when working at the other one - if you do, check the box "Allow network users to change my files"
Click OK.
At the other machine, you can now double click "My network places", Select Entire Network/Microsoft Windows Network. Double click the name of your workgroup and you should see you other machine. Double click and you will see the folder that you shared.