I'm pretty sure you can do this with a hot-corner and the built-in VNC server. (You would need a VNC viewer for iOS, there are LOTS of them.
You could also create an applescript:
tell application "System Events" to sleep
and run it using the VNC connection.
Alternatively, you can turn on ssh, ssh in, and issue the command:
pmset sleepnow (See the pmset man page)
to put the mac to sleep.
This would require a ssh client for iOS. Again, there are a LOT of them. Personally, I have used iSSH, and it works fine.
As @mankoff stated in a comment, RowMote states in it's store description:
- SLEEP AND WAKE: Put your Mac to sleep by holding the Play button for 3 seconds while controlling any Apple application, just like the
hardware remote. Rowmote automatically wakes up sleeping machines
which are connected via Ethernet!
So far as I know there isn't a nice automated way to provide the benefits of System Restore as it is implemented on Windows. For all its utility for Windows users, though, System Restore can't be used to backup/restore individual files & whatnot at the whim of the user - that requires a separate backup system.
Time Machine on OS X, on the other hand, can provide for the backup/restore of deleted documents, folders, etc, and can be used to restore an entire hard drive in the event of a crashed or munged drive. I've used this function a few times, twice on a very important server, and once on my own machine, with great success.
My Mom's new Lion iMac is setup with an inexpensive external 500 GB USB hard drive and Time Machine is running like clockwork. My Mom knows to check the Time Machine menu every day to make sure it is backing up. She's even started to recover files on her own now, without needing to call Tech Support (me).
Time Machine was also very helpful in migrating her creaky Leopard Mac mini to the new iMac a few months ago. Instead of hooking the old & new Macs together via Ethernet cable, I simply ran a Time Machine backup on the old machine, shut it down, connected the USB drive to the new iMac, and the Migration Assistant app took care of the rest. Her new iMac was up and running in a little more than an hour.
A non-Time Machine solution would be using Carbon Copy Cloner or SuperDuper! to back up the Mac to an external hard drive on a regular basis. This would allow for a mass restore of the drive's contents.
Another non-Time Machine solution would be to boot from the System Install DVD (pre-Lion)
or an bootable external HD (Lion & after) and create a restorable disk image. After converting the image to ASR format, Disk Utility can be used to restore the disk image.
Best Answer
The Mac comes with the server part of the software built-in for "Apple Remote Desktop"; They can be viewed and managed remotely if you have the client software. For most of us that's too expensive a solution, so an alternate is to use VNC. Check out JollysFastVNC and Chicken of the VNC.
Also, iChat, which comes with the Macs, can do screen sharing, which might be all you need. Check out "Share and share alike." from Apple's iChat site and "Sharing your screen with a buddy".