A long, long time ago, I went to Maker Faire NYC. To be precise, 4 months ago in September. While at Maker Faire, I bought a Spurtbot kit from ignoblegnome, and I have finally built it! I'd like to thank him for putting these kits together, it works really well. The parts are cheap ($8), but it still follows a line pretty well.
I followed the instructions pretty much to the word, although instead of hotglue I built the chassis with superglue and double sided sticky tape. Also, I found that the resistor that he gave me didn't work so well. My multimeter measured it at 48 ohms, and I think the current to the IR resistor made it to "bright", so that the sensor read a reflection even while it was over black. I swapped out that resistor with an 82 ohm one, and that helped a lot.
That's pretty much all I have to say... you can check out ignoblegnome's post here - http://letsmakerobots.com/node/28235 Enjoy the video, peace out!