The (MDP2HDMI) adapter has audio support, so it can be used with Apple's new , which come equipped with audio-enabled Mini DisplayPorts. (MacBook Pros previous to the recent models have video-only Mini DisplayPorts.) The adapter sells for $29.
If you want to connect to a DVI display, you can use StarTech.com's (MDP2DVI) adapter. It supports video only and is priced at $29.
The (MDP2VGA) adapter allows you to connect a VGA monitor. It sells for $29.