What I always personally recommend is to find an older laptop (some halfway decent Pentium III or P4m machine) and install Debian on it. Then, do apt-get install netatalk and then also get either samba or ssh and use one of those methods to connect modern computers to it.
You can either put the old laptop right next to the mac and use a localtalk to ethernet bridge or you can put ethernet in the 575.
This will give the Mac access to all of the space available on the Debian machine in a way that works extremely well and can be relatively fast, so it may even reduce the need to buy a second hard disk for the 575.
Also! It can be run in Virtual PC or VMWare Player or VirtualBox on your existing PC if you either don't have an older machine around, or don't want to bother setting it up. Debian will offer decent performance while virtualized, even with relatively low ram. (you could probably set the latest debian to use 96 or 128mb of ram if you were *only* running netatalk and either samba or ssh on it)
You can either put the old laptop right next to the mac and use a localtalk to ethernet bridge or you can put ethernet in the 575.
This will give the Mac access to all of the space available on the Debian machine in a way that works extremely well and can be relatively fast, so it may even reduce the need to buy a second hard disk for the 575.
Also! It can be run in Virtual PC or VMWare Player or VirtualBox on your existing PC if you either don't have an older machine around, or don't want to bother setting it up. Debian will offer decent performance while virtualized, even with relatively low ram. (you could probably set the latest debian to use 96 or 128mb of ram if you were *only* running netatalk and either samba or ssh on it)