How do I make a curved edge in photoshop?

you can use the path tool, and convert it to a mask
or you can make a mask and smooth the border.

I zoom in all the way and make the curves pixel-by-pixel. There’s probably a complicated, yet simpler way to do it.

http://www.youtube.com/watch?v=cbGzWOtwSSE

I decided to take the lazy route and delete the backround, making the outermost area blank.

Select what you want with the eliptical marquee tool, then do command shift i to select the outside of the marquee part and hit delete. What is left is what you want.

The best way is to use the Rounded Rectange Tool set to Paths and then make a selection of the path that is produced, giving you a rectangle with a curved edge.

I made a quick little video that will walk you through doing this.

Ctrl click the layer with the image in the little layers window at the bottom then go to Select > Smooth. (Sorry I don’t have Photoshop on this computer so i’m not exactly sure) Then just put a few pixels like 3. That should smoothen the edges of the selection.