While I see "Wake on LAN" on my 10.5 and 10.6 machines. I don't see it here with 10.7.x.
But, as has been said before, one of the easiest ways to wake a mac without a keyboard and/or need for one is via screen sharing. I know I do this multiple times a day from either my laptop down in the kitchen to my mini here in my office upstairs, or my wife's macbook across the hall. Works every time, and does not necessitate the install of yet another program.
So unless you are running your mini CLI, this seems to be the easiest fix for the issue at hand.