Red Wave Radio

I'm in the process of designing a unit that hopefully will be able to decode  
DTMF as well as recognize PL tones. Building the DTMF half shouldn't be a
problem, but I'm pretty new at this, and need a recommendation on a chip to do
the PL tone decoding. Can I just use a standard tone decoder chip (not DTMF)?
Also, will there be any problems with taking the speaker out of a scanner or
HT and routing that into the unit? Will the tones be to low? (Is subaudible
carried over the speaker out?)

Thanks
-Bill