With a suitable sound card or sound cards and leads the Xenyx802 will work with PlayIt Live.
It's arguably not an ideal mixer for radio (rotary rather than linear faders and no built in USB - unless you have the Q802USB)
If you have the 802 (not Q802USB) then reasonably controlled speaking and a level that is a bit higher than the music will help. Some bass cut is also generally a good idea and perhaps a little mid boost (-6dB of bass cut and 3 dB of mid boost would be my starting point).
You won't sound like yourself to you (when you hear yourself there is conduction within the head) but try that sound on someone who knows you and see what they say.
Generally a "decent" microphone will help.
Personally I would also probably recommend a condenser rather than a dynamic (which will require the phantom power turned on).
Have a listen to the microphone comparison videos at Studiospares.
just out of interest can i use my xeny802 mixer with playit
and one of my staff said that mic is not sounding professional?
how can i make it sound pro in playit