Another question: I am knitting in Sk st and it says to bind off 7 sts at the beginning of the next two rows. When I am on the WS (purl row) do I bind off in purl? Is there such a thing? Or do I bind off in knit and then finish the row in purl?
You can bind off in purl if you are on a purl row - just purl as usual and pass the stitches over as you go, as in a knit bind off.
The bindoff is actually only the part where you pass the stitch over the other, the rest of it is done just like a regular row.