Here's a good site for sewing invisible zips

So easy to sew invisible zips

Try this URL when you have time. Please note you do not have to tack the zip first, just sew in the middle of the zip tape first then pull back the zip teeth to sew underneath. A normal zip foot will do the trick if you carefully fold back the zip coil just before you sew each section.

Always sew the seam that will be attached to the base of the zip after you have sewn the zip as instructed.

Zip link

http://www.youtube.com/watch?v=RneYzsqOyD0&feature=related