Just found this and it seems the G3 has been squashed. I guess 10.6 will logically scrap the G4 as well
You must have a Macintosh computer with:
an Intel processor or a PowerPC G4 or G5 processor
a DVD drive
built-in FireWire
at least 256 MB of RAM for a Power-PC based Mac and 512 MB for an Intel-based Mac (additional RAM is recommended for development purposes)
a built-in display or a display connected to an Apple-supplied video card supported by your computer
at least 6 GB of disk space available, or 8 GB if you install the developer tools
Link to article here.
You must have a Macintosh computer with:
an Intel processor or a PowerPC G4 or G5 processor
a DVD drive
built-in FireWire
at least 256 MB of RAM for a Power-PC based Mac and 512 MB for an Intel-based Mac (additional RAM is recommended for development purposes)
a built-in display or a display connected to an Apple-supplied video card supported by your computer
at least 6 GB of disk space available, or 8 GB if you install the developer tools
Link to article here.