Joe van Tunen - 2012-10-09

Use the Mac's built-in Startup Manager by holding the option key at startup.
http://support.apple.com/kb/HT1310

Then use the Startup Disk System Preferences panel to reselect Mac OS X as your startup volume. When Mac OS X starts up again, rEFItBlesser should automatically set rEFIt as the startup program. Then when you restart a third time, rEFIt should appear.

If rEFIt doesn't appear, then it might mean that rEFItBlesser is not properly installed. In that case, try running the rEFIt installer again.