You need 1GB of Memory , i.e. 2x 512 or 1x 1024 RAM modules ( more is better , as always ) . But all other hardware, Intel CPU and so should let run Snow great on it.
You can buy the Update DVD and choose update current OS. 10.5 to 10.6 will keep your data intact. Some apps might needed to be update by you manually, but most Leopard apps , especially if they are Universal or Intel still run in Snow with no problems. System-deeply Tweakers like "ONYX" "Cache Cleaners", "MacPilot" etc. must be updated always to support the new OS. Best is to delete such before you run the upgrade process for the OS, then get the Snow-comaptible ones after the OS is replaced with the new one.
Your ppc only apps will continue to run, if you do a custom install and choose "Rosetta" to be included. But even if you miss this part - launching a Leopard ppc application will simply offer to download Rosetta ( the ppc emulator engine for Intels ).
Beware however to net get used too much on Rosetta// ppc apps - Apple removed this technology in Lion, so Snow is the last possible OS to run old software written originally for G3/G4/G5Powermacs.
Message was edited by: Sjazbec
Snow Leopard/10.6.x Requirements...
* Mac computer with an Intel processor
* 1GB of memory (I say 2GB at least)
* 5GB of available disk space (I say 30GB at least)
* DVD drive for installation
* Some features require a compatible Internet service provider; fees may apply.
* Some features require Apple’s MobileMe service; fees and terms apply.
Which apps work with Mac OS X 10.6?...
It looks like they might still have it...
If it's a core Duo & not a Core2Duo, then it'll only run in 32 bit mode.