I'm looking at setting up a HTPC, to act as a central server for all my music, movies, etc. I want to be able to use features such as MythTV's pausing/rewinding of live television, and I have one other essential requirement. I want to be able to access my mp3 music collection without using the TV as a display. This would mean using some device with a screen, and bi-directional wireless communication.
So far, the best ideas I've come across involve using a PDA, connected via bluetooth or 802.11b, which should allow the PDA to connect to whatever program is running on the server, and pull down track information etc.
Does anyone have any ideas about software/hardware that allows me to do this? Or am I asking for features that aren't really mature yet?

Check out Salling Clicker 3.0 at http://www.salling.com
It supports a large amount of devices and is fairly customizable. I'm currently using it to control (among other things) iTunes on a Mac mini from an Axim X30 PDA over WiFi (it also supports Bluetooth).
The current track (including artwork) gets displayed on the PDA's screen, and it's very fast.
You can download a limited version from their web site (it disconnects after 30 clicks) that's more than sufficient to find out if it will do the job for you or not. A full license is $24.

Now if I can find a USB infrared blaster with scriptable OSX software (is the ZephIR still around?) I got myself one sweet home automation system for dirt cheap :)