Serging around curves - I would love to make a scarf with curved edges but have had no luck serging curves -- the stitching seems to separate from the fabric. Any tips?

It gets easier with practice - not what you wanted to hear, I know :)
Overlocking/serging is different to using a regular sewing machine because with a sewing machine the foot is smaller (in length) and so you an maneuver around corners quite easily however with an overlocker you need to try to feed the fabric into the back of the foot in a straight line rather than trying to turn the fabric. Go as slow as your machine will allow you to at first and you'll get the hang of it. It's so much easier to explain this by showing though, rather than telling, so I agree that maybe there might be some helpful videos in youtube :) Keep at it. I love my overlocker ;) xXx

Oh and another helpful tip, cut your fabric layers larger than your pattern, tracing the pattern onto the fabric (crayola markers wash out) and use your overlocker's blades to cut the pattern to size while you're stitching. When I make nappies/diapers, which have curves in, out, and around, I trace my pattern so that the seam allowance is included and then cut off the marker as I go. It's much easier this way than cutting your pattern to size and then trying to keep all layers together as you overlock.

I agree agree with Dec716, below, The only other way is by using an industrial style machine fitted with a 'servo motor' which allows you to serge at very low speeds without affecting the stitch layout and/or density.

This is one of those things that takes practice. The sharper the curve the more difficult. It helps if you have a clear presser foot so you can see your work better. You might try youtube for demo videos