My frequency counter kit arrived today from SparkFun.com. The board wasn't exactly as described on nuxie1.com but it was easy to put together. I put a red LED from my stock on it instead of the supplied green LED. I connected it to my USB hub, tweaked the LCD contrast, and there it was: 0 hz.
The circuit board was nicely done. When they added a USB miniB SMT connector they crowded the LCD contrast control against the 6 pin ICSP connector, but it looks like it will still work. The ICSP header wasn't included in the kit, so I added one, again from stock.
I want to build some radio frequency circuits, so hopefully this will help me tune them up. I'll probably add a divide-by-ten front end to it and some signal conditioning. The kit claims to work to 2MHz or higher. If I can get it up to 30 MHz with a prescaler I think it will suit me fine.