I designed a simple PC board for the Microchip MCP2200 in Eagle and had some boards made at DorkbotPDX. They turned out really nice. This chip is a preprogrammed version of Microchip's PIC18F14K50. As well as being a good serial converter, it also has eight GPIO pins.
The board is definitely larger than necessary. I'm still learning. I have a much smaller one already drawn up, but haven't had any boards made yet.
Here I'm testing the board out with a PIC 18F2550
If you want to make your own board just download my Eagle schematic and board layout. You'll also need my Eagle library. This file set is for the DorkbotPDX PCB service. You may possibly have to make changes for other PCB services - I don't know.
Here's a look at the board layout:
And a schematic:
Video of the board being tested: