sync ipod touch contacts and calendar to imac

I may be dense but.... (no wisecracks please).

I recently bought a new iPod Touch. One of the things I use it for is an address book and a calendar-keeper. I find instructions for syncing the iMac information to the iPod, but no way to do the reverse.

As I am out and about with the iPod in my pocket, this is often where the changes happen. I would like to have them updated on the iMac.

My old PDA did just that; checked for the latest revisions to entries on the computer and the PDA and them synced them so they matched. I'd like to do the same easily with my iPod.

I have a brand new iPod touch. I am backing up contacts aand calendar to the iCloud.

I am using an Intel Mac with system 10.6.8

Sync works fine taking changes on the computer to the iPod.

Thanks,

Ken