In addition to those Jan mentioned (Branching Out was my first lacey type scarf) I also have a few in my queue on ravelry that can be made using sock yarn.
This first one is called Woodland Shawl, it's a free pattern and I saw a few people on ravelry used Trekking, which caught my eye because I have a ball of Trekking that might want to be a scarf. To do it as a scarf the pattern tells you to cast on fewer stitches to start.
Also this one is free, uses Trekking, it's called "Trekking is for Necking" if you're on ravelry.
I also like this one, called That Little Scarf. It's not free ($5) but it is downloadable.
And finally, Falling Water. I made this one recently out of a worsted weight and really liked the pattern. But it's written for fingering weight and I've seen it on ravelry in many different yarns and it's always pretty.