i'm a drummer myself and i have to play to click tracks cos the band i'm in at the moment doesn't have a bass player or 2nd guitarist yet. the way i do it is as follows:
1. open a new song in logic
2. create however many tracks i need for backing instruments including the click
3. upload a cowbell sample to track 1 at point 0.000
4. copy the sample to beats 2, 3 & 4 of bar one (using 4/4 time for his example)
5. repeat the region enough times to last the whole song
6. record the backing instruments on the remaining tracks
7. pan the click hard left and the music hard right
8. connect the right output of my soundcard to the pa and listen to the click through the headphone socket of the soundcard
it works for me, but obviously theres other ways to do it. like connecting a drum machine to the midi output of your soundcard
hope this helps anyway