Suggestions for remote audio control?

[Laughing Mechanicus]

My TV has crappy built in speakers, so I recently plugged in a decent 2.1 set of computer speakers to its line-out socket to get some better sound quality and bass. The only problem with this set-up is the line-out audio signal from the TV doesn't change volume based on the TVs volume, so the only way to change the volume (or mute it) when switching between various sources is to use the volume knob on the speakers themselves, which is awkward.

I have previously seen little infra-red volume controls which you plug in between the speakers and the computer (TV in this case) and let you control the volume via remote. Unfortunately Google hasn't turned up very much so I was wondering if anyone had any suggestions for where I could find such things (brand names etc...) and what to look for in them? The speakers use the standard 3.5mm audio jack.

[Laughing Mechanicus]

No suggestions?

The best I've found so far is a build-it-yourself kit that does what I want, so I will probably end up getting that.