Hi Malc

Assuming your PIC doesnt need to do anything else until the next beat then wait for the beat to disappear

Code:
music:

read patt[swcount],steps                ;read the first value of the selected patter and place it in the variable steps
    READ PATT[SWCOUNT]+ C,PORTB         ;reads the step value for selected pattern and send it to PORTB 
           If switch2=1 then C=C+1
           pause 10
           If C=steps then C=1
         ****** add a bit here ******
goto music:
Add these lines at the point shown or if you need to update the display first then add the after you have updated the display.

Code:
        While Switch2=1   ' beat signal is still high
            pause 1          ' short pause
        Wend                 ' its gone low now so we can carry on
Hope that helps