They're pretty easy once you know muscle actions. If you're looking online, look at some ATC programs' websites as well, I've seen a few lists.
As for the grading system:
1=trace contraction, no movement
2=Some joint movement, none against gravity
3=full movement against gravity
4=full movement against gravity and some resistance, phasic shake with full resistance/break test breaks the position
5=able to hold against gravity and full resistance/break test.
3- would mean partial ROM against gravity (which means that if someone has decreased ROM, while they may have local strength of 4/5 the whole muscle is graded a 3-), 3+ is similar to a 4, and I think is the minimal strength required for weight bearing activities.
The important thing to remember is what the gravity-eliminated position is for each muscle. Also important, of course, are possible compensatory movements and where to stabilize, as well as where to resist (i.e.-resisting on the palm for a biceps Brachii MMT is bad, since you're crossing two joints).
