SQL Server has the ability to create a central location where you can push out certain SQL Agent Jobs to run on other servers. This feature is called a MSX/TSX arrangement, and it's been around for a while.
In SQL Server 2005, you didn't want to use SQL Server 2000 systems as targets, because the SQL Agent subsystem was just too different. You can, however, use SQL Server 2008 to push SQL Agent Jobs down to SQL Server 2005 systems - I use this feature in my environments today. Just make sure that you don't use any new SQL Server 2008 features (such as PowerShell Job Steps) or syntax (such as MERGE) in your Job Steps.
If you do, you'll cause an error where the job won't copy down to the Target Server. Make sure you deal with that right away, since the Agent uses a queue to send the Jobs out. You'll block all of the other Jobs that you need to send down until you deal with the issue.