Upgrading to Leopard

I am using OS 10.3 right now, is it possible to upgrade my OS to Leopard directly or I have to install Tiger first and install Leopard after installing Tiger?
For the reqirements, I checked its system requirements, and my mac can run Leopard.

Not necessary! My only advice is to do a full backup first. Any system upgrade is a cardiac workout for a drive, especially one that might be getting along in years! Then the usual, run Disk Utility --> Repair Disk. Directory errors have a way exploding during an upgrade. Good luck!

Most of the early converts to Leopard, I have not gone to Leopard, found that an Archive and Install is successful or Erase and install. Either way - make the backup. Do not do the install over Panther, unless I am corrected, as this leads to lots of little problems.

As long as you follow some basics, directory repair, permissions repair, enough free space, enough ram, remove any USB and Firewire devices (except the keyboard and mouse!) then you should not have any problem going from 10.3 to 10.5. That said, there may be programs that are not compatible with 10.5.

And one more thing, how is Tiger different from Panther? And how Leopard is different from Tiger? Is Leopard really better? And how is Panther better than Jaguar? Is Leopard stable for my "OLD" G4, will it crash?

Thomas I use Leopard on an old, CPU upgraded G4. With sufficient RAM it is very fast and have found it rock steady with not one crash since OS was released.

Not a fan of archive and install but prefer a clean install which wipes the drive clean.

You do not give your computer specs so don't know how you will find it but it is like everything else in life - you gotta try it to appreciate it.