This is becoming one of those must do effects,so I thought I'd tell you how I do it.
1)new project,place your music track on the timeline.
2)Open Windows sound recorder (start>programs>accesories>entertainment)
3)make sure windows recorder is set to record from your mic.
4)Start your track playing in studio and click the record button in "recorder".
5)Tap your mic in time with the beats.
6)Recorder will record up to 60 secs of audio (I'll tell you how to record more at the end).
7)when you've recorded 60secs,Save the file in your prefered directory.
8)Import this file into Studio via the sound effects album.You should be able to "see" each beat in the audio waveform.
9)Trim the start and end of the "beat track" to a beat,I nomally trim the first few beats out incase my timing was a bit off at the start.
10)Drag the beat track back and forth untill your beats match those in your music.
11)Now you have it synced just copy and paste the beat track till it is the full length of the music.If the beats don't show up well,you may want to razor the original beat track at each beat,then copy and paste all the bits to make finding the beats easier.
12)As you add your clips or stills,just make sure you trim them to end on a beat.
To make recorder record more than the default 60secs,Make a copy of your music track (recorder will record over it)and use file>open in recorder to open it,recorders length will now be the length of the music track.