Here are the models of G3 Powerbooks:
G3/250 - December 1997 Kanga - not upgradable to Mac OS X and based on the Powerbook 3400 architecture. Color Apple logo on back. Only in 12.1"
G3/233, 250, 292 - May 1998 Wallstreet - in 12, 13, and 14" models.
G3/233 with 512k backside, 266, 300 - September 1998 Wallstreet II (a.k.a. PDQ) - in 12, 13, and 14". Last to employ Serial and ADB interfaces. Every model very easily upgradable to Mac OS X once you made sure you had a hard drive of at least 6 GB. Give yourself 3.5 GB of free space to install. If your hard drive is 8 GB or above, partition the first 7.95 GB to install Mac OS X on, or else it won't install. Last to employ separate cardbus and PCMCIA ports.
Now one of these early models was also codenamed Main Street.
G3/333 and G3/400 - May 1999 - Lombard. First to have built-in USB, but still have SCSI. Lots of difficulty upgrading to Mac OS X due to problems with CPU. Smaller drive bays than the earlier models.
G3/400 and G3/500 - April 2000 - Pismo, Powerbook 2000. First to have built-in Firewire. Last to have 2 Firewire ports until the 17" Powerbook. Some 400 Mhz models still had difficulty upgrading to Mac OS X. 500 Mhz should be fine for X.
The Titaniums all had G4s, 1 Firewire port, and no drive bays.
For more specs see: http://www.info.apple.com/support/applespec.html#powerbook
G3/250 - December 1997 Kanga - not upgradable to Mac OS X and based on the Powerbook 3400 architecture. Color Apple logo on back. Only in 12.1"
G3/233, 250, 292 - May 1998 Wallstreet - in 12, 13, and 14" models.
G3/233 with 512k backside, 266, 300 - September 1998 Wallstreet II (a.k.a. PDQ) - in 12, 13, and 14". Last to employ Serial and ADB interfaces. Every model very easily upgradable to Mac OS X once you made sure you had a hard drive of at least 6 GB. Give yourself 3.5 GB of free space to install. If your hard drive is 8 GB or above, partition the first 7.95 GB to install Mac OS X on, or else it won't install. Last to employ separate cardbus and PCMCIA ports.
Now one of these early models was also codenamed Main Street.
G3/333 and G3/400 - May 1999 - Lombard. First to have built-in USB, but still have SCSI. Lots of difficulty upgrading to Mac OS X due to problems with CPU. Smaller drive bays than the earlier models.
G3/400 and G3/500 - April 2000 - Pismo, Powerbook 2000. First to have built-in Firewire. Last to have 2 Firewire ports until the 17" Powerbook. Some 400 Mhz models still had difficulty upgrading to Mac OS X. 500 Mhz should be fine for X.
The Titaniums all had G4s, 1 Firewire port, and no drive bays.
For more specs see: http://www.info.apple.com/support/applespec.html#powerbook