I tried it for the first time this spring, and I'm happy to report it worked great! Here's what I did:
First I soaked my seeds overnight (each type in its own section of an ice cube tray). That made them sort of sticky.
Then I laid toilet paper out on a plastic tablecloth, misted it with a spray water bottle, and spaced the seeds out onto it with measuring tape as a guide. Then I folded the tp over and voila! seed tape.
The only tricky part was making sure the tape didn't blow open/away when I brought it outside. I guess that would be less of a problem if you use Elmer's glue as some people suggest, but since I wasn't planting a ton of rows, it wasn't really a big deal for me. It was so much easier than bending down to plant each individual seed! All I had to do was make a trench at the right depth, lay the tp tape on it, and bury it with soil. All of the hard part was done while comfortably sitting on my couch. :-)
Here is a piece of radish seed tape getting buried:
And the result about a month and a half later. I think they're spaced pretty nicely, considering I didn't do any thinning at all!
The carrots and turnips I planted with the seed tape worked pretty nicely too. It is a little tougher to see since some clovers have since popped up around the carrots that I still need to weed - but you can see 3 distinct rows of carrots & 2 rows of turnips. All with no thinning at all. I will never do it the old way again!