Thank you for the two links, especially those from OWC -- from whom I've been mulling the SSD purchase. And despite the shipping costs, I almost always buy outside Japan, and have for the last 17 years I've lived here. Further, I get paid in Japanese Yen, and you know what the Yen to Dollar exchange rate is these days! 
With regard to that and other cardbus USB adapters, one thing I've noted is that you must have OS X installed on your PowerBook G3 before you can use USB2 speeds. Otherwise everything slows down to USB1 speeds, which is fine for a mouse, but painful in the extreme for any data related transfers, especially when you are talking about 20GB or more of data. More specifically, it seems that USB2.0 won't work on OS 8.x or 9.x at all, simply because of the lack of OS-level driver support for such.
In light of this, it may make more sense to go with what you are using now -- a cardbus firewire adapter. Even the firewire adapters won't work under OS 9 or earlier, right? If not, then the situation is the same as the USB cardbus adapters, except that the FIrewire adapter would theoretically be faster (when used under OS X). Of course, that would require me to purchase a Firewire case for the 2.5" IDE spinning platter drive, but I see that OWC sells those too.
So what are your thoughts on comparing a USB cardbus solution vs. a Firewire cardbus solution? (In terms of raw speed and compatibility.) And would you recommend a specific Firewire cardbus adapter?
Also, is there any other solution that might be considered OTHER THAN a USB or Firewire cardbus adapter, in order to clone the internal 2.5" drive to a second 2.5" drive. For example, what if I put the SSD in one of my Wallstreet's and then connected it to the other Wallstreet via Target Disk Mode. I would need to do that via SCSI though. And I've never tried it. Nor do I know if they even made HDI-30 to HDI-30 cables for that purpose.
Thanks again!
With regard to that and other cardbus USB adapters, one thing I've noted is that you must have OS X installed on your PowerBook G3 before you can use USB2 speeds. Otherwise everything slows down to USB1 speeds, which is fine for a mouse, but painful in the extreme for any data related transfers, especially when you are talking about 20GB or more of data. More specifically, it seems that USB2.0 won't work on OS 8.x or 9.x at all, simply because of the lack of OS-level driver support for such.
In light of this, it may make more sense to go with what you are using now -- a cardbus firewire adapter. Even the firewire adapters won't work under OS 9 or earlier, right? If not, then the situation is the same as the USB cardbus adapters, except that the FIrewire adapter would theoretically be faster (when used under OS X). Of course, that would require me to purchase a Firewire case for the 2.5" IDE spinning platter drive, but I see that OWC sells those too.
So what are your thoughts on comparing a USB cardbus solution vs. a Firewire cardbus solution? (In terms of raw speed and compatibility.) And would you recommend a specific Firewire cardbus adapter?
Also, is there any other solution that might be considered OTHER THAN a USB or Firewire cardbus adapter, in order to clone the internal 2.5" drive to a second 2.5" drive. For example, what if I put the SSD in one of my Wallstreet's and then connected it to the other Wallstreet via Target Disk Mode. I would need to do that via SCSI though. And I've never tried it. Nor do I know if they even made HDI-30 to HDI-30 cables for that purpose.
Thanks again!