There is a way, but you would be better off buying a 320 GB SATA drive.
In Windows, if all three drives are empty (no partitions), you can use Disk Manager to create a Spanned volume. It uses space from each drive indiscrimately. It's definitely not striped, the spanning mechanism can be as simple as use drive 1 until it's full, then add new files to drive 2.
Look up Spanned Volume on Google and let us know if you need more help. If it works, let us know that too. Good luck.
Note that a single drive failure will blow away all of the data.