For those of you who are tired of staying on OS X Tiger, I will help you then. This tutorial will show you how to get Mac OS X Leopard on your computer VIA USB
Step 1: get a bittorrent (I recommend uTorrent, here is the download link: ttp://www.oldapps.com/mac/utorrent.php?old_utorrent=9844)
Step 2: go to: http://thepiratebay.se/torrent/4687503/Mac_OS_X_Leopard_10.5.6_Full_Retail and click on Get This Torrent. The large download buttons are just fakes.
Step 3: Download the torrent
Step 4: Mount the image you just downloaded
Step 5: Open disk utility
Step 6: Plug in a USB Drive (8gbs minimum)
Step 7: Select your USB Drive
Step 8: Go to partition
Step 9: Click Volume Scheme and select 1 partition
Step 10: Name it: Mac OS X, for format, select Mac OS Extended Journaled
Step 11: for options, select Apple Partition Map (this is very very important)
Step 12: After, click on restore, drag your .dmg file to Source and drag your Mac OS X usb drive to destination.
Step 13: Click restore and wait 40~ minutes
Step 14: Restart your computer while pressing ALT-COMMAND-O-F
Step 15: You will have a white display, release what you are pressing
Step 16: type boot ud:,\\:tbxi and Mac OS X should start booting :)
If you have any questions please comment and I'll happily answer :)
Have fun with Mac OS X Leopard!!