The requirements for Leopard are any Intel, PowerPC G5 or G4 (867 MHz and faster). The clamshell iBooks, available between 1999 and 2001, have a G3 processor (300-466 MHz) which will not support Leopard.
Mac Leopard is not a person. It is a piece of desktop software developed for the Apple Mac computers. Its full name is Mac OS X Leopard and one can find more information on the Apple website.
Likely never. Snow Leopard is a $29 upgrade to Leopard, but it requires a Mac with an Intel processor (newer than 2005) and 1 GB of RAM.
Snow Leopard is an upgrade to Leopard and so you will need Leopard installed on your Mac before installing Snow Leopard. For Mac computers with an Intel processor running Tiger you will need to purchase the box set that includes iLife 09 and iWork. (See links below)
Mac "Lion" and Mac "Snow Leopard" refer to iterations of Apple's Mac OS X (operating system, version 10). "Lion" is the newest as of this writing, and is version 10.7, while "Snow Leopard" is its immediate predecessor, and is version 10.6.
An iBook G3 Clamshell needs to be running Mac OS X 10.3.4 (or later) for iLife '05 to operate. Depending on the particular version of Clamshell there may be problems with the amount of hard disc space available for the iLife applications.
10.5, Snow Leopard is 10.6
To upgrade from Mac OS X 10.4 (Tiger) to 10.5 (Leopard) you will need to buy a boxed version of Mac OS X 10.5. If you have a Mac with an Intel processor you can go straight to Mac OS X 10.6 (Snow Leopard) which is a cheaper upgrade option.
Currently, it's $129 dollars (Mac OS X Leopard). Once Snow Leopard is available (August 28), it will be a $30 dollar upgrade from Mac OS X Leopard.
Although the appearance of Mac OS X 10.5 (Leopard) and Mac OS X 10.6 (Snow Leopard) is similar there are many differences in the workings of the two systems. Most notably Snow Leopard requires a Mac with an Intel processor whereas Leopard will run on earlier Macs with G4 or G5 Power PC processor as well as the newer Intel based Macs.
Mac OS X 10.6 (Snow Leopard) will not work on a Mac with a G4 processor as it requires an Intel processor based Mac. A G4 (867 MHz and faster) can run Mac OS X 10.5 (Leopard).
Mac OS X 10.5 is known as Leopard. The last available version of Leopard was 10.5.8.
Yes, Mac OS X 10.5 Leopard ships with Java support.