I am just starting out knitting and could always use some needles-- Every pattern I like uses more than one set!! Also what is a PM?
Ah, depend on where you see it. In threads in this section it is most likely to be a private message. Click on any member name to the left of a post and you will see an option to send a PM to that member.
In a pattern, PM would be place marker and later you should also see MM for move marker.
Amy (originator, author, star, knitter-in-chief, and Grand Poobah of the KH site) has an abbreviation thread that list the common initialisms here.
Ah but she didn't put PM in the list.. yet.
Master of Crochet, apprentice of Knit