How to sync all my Exchange files (including Notes and Tasks) to my Nexus S?
Try NitroNote - it offers syncing for Outlook Notes. You'll need to install apps on your desktop as well as the device.

There's also the more powerful TouchDown client which will sync email / contacts / tasks from an Exchange server.

Finally, lots of users claim to find gSyncit to work well for them, but YMMV.