If you have a Baofeng UV5R Ham Radio and want to get the most out of it have a look at the reverse engineering work Lior Elazary has done with his. The radio is very powerful as it is but when hacked, the sky is the limit on what you can do with it. Lior has many pages of information and code that he has used to hack this radio for his own needs and interest.
“I figured out how to interface with the voice chip. Its very easy. In the process, I also found out a good way of experimenting with the MCU in place. I cut the Vdd traces going into the MCU and added jumper wires instead (there are two vdd lines going into the MCU with the trace exposed). This allows me to turn off the cpu whenever I want to send my own signals, and turn on the cpu whenever I want to see what the cpu is doing. I also soldered very thin wires (I used a single strand from a multi strand wire) on the the legs of the MCU so I can attach the probes and sniff the logic data or replay the data.”