I am upgrading my older G5 (10.4.11) with the Tiger OS to Leopard (10.5.6) from an Apple disc, I would like to know if anyone has done this and if they had any problems in the process?

Hello,

I've done it on my G5 & many G4s, no problems.

For safety...

"Try Disk Utility

1. Insert the Mac OS X 10.5.6 Install disc, then restart the computer while holding the C key.

2. When your computer finishes starting up from the disc, choose Disk Utility from the Installer menu at the top of the screen. (In Mac OS X 10.4 or later, you must select your language first.)

Important: Do not click Continue in the first screen of the Installer. If you do, you must restart from the disc again to access Disk Utility.

3. Click the First Aid tab.

4. Select your Mac OS X volume.

5. Click Repair. Disk Utility checks and repairs the disk."

http://docs.info.apple.com/article.html?artnum=106214

One more secret...

1058 Combo Update, 10.5.8...

http://support.apple.com/downloads/Mac_OS_X_10_5_8_Combo_Update

Repair Permissions afterwords, reboot.

In fact you have to Repair Permissions twice in a row after applying that combo update.