I have been using a DDS Kit from here. Works good from 1 to 70 mhz.http://www.amqrp.org/kits/dds60/
Very nice quality DDS kit. I have interfaced this kit with a PIC and added an encoder and keypad for frequency selection, and LCD display to show the output frequency. I have also written a Delphi application that is interfaced through a USB to rs232 FTDI IC that allows me to control the frequency output to the DDS with my laptop with gives the best accuracy. Reason for better accuracy is the ability of the PC to perform better floating point math operations when calculating the control codes for the DDS.
You will not be disappointed with this module (kit) I have bought 3 of them already.