Back at the 64-bit mark. Last friday Apple released it’s latest operating system: Snow Leopard. After dumping IBM’s PPC 64-bit, and switching to Intel, computing has returned to the Macintosh! So back to the past?
Big difference
All standard programs are ported to 64-bit, Safari, and Finder run in 64-bit modus. It’s noticeable when you first start your Apple, [...]

I’m using the Apple FileVault encryption tool that comes with Leopard as standard. There are a view problems with it.
One of them is: “resetting default applications preferences”. Extensions in Leopard are linked to Applications. The FileVault has a bug. It’s possible to change the extension preference but when restarting all defaults will reset.
Solution

Download a program called Lingon.
Add a new [...]

To change your mac address at Leopard OSX there is a little ‘trick’ that is required. The regulair command with ifconfig does not do the job.
Start your terminal and run:
Airport

Enable airport but disconnect from network.
/System/Library/PrivateFrameworks/ Apple80211.framework/Versions/A/Resources/airport -z
sudo ifconfig en1 lladdr [new mac]

 
Ethernet

no Fix yet, if you know any let me know.