Another post here got me thinking about this. If you can build it, you can keep an eye on your toe, or set it to whatever you want if it's wonky.
For some of the pickier types, you can set your toe after a front end rebuild so you don't have to worry about scuffing the tires on the way to the alignment shop.
If demand so dictates, I could probably do up a more detailed drawing soon.

To use it, you slide it under the front of the car, get one end up against the front or rear of the tire and measure the distance from the toe checker to the other tire. slide the checker from the front to the back or the back to the front and compare measurements. For toe-in, the measurement should be bigger in the front of the tire and for toe out, the measurement should be bigger at the rear of the tire. Good for quick and dirty, or if you are careful, you can get pretty accurate measurements with it.
If Fo_fdyfo doesn't already have one, I bet he's got one by the end of next week. :D

Luck,
K

http://www.chevelles.com/showroom/toechecker.jpg

You could buy these or, very easily make them.
http://www.speedwaymotors.com/xq/asp/strBase_List./hilt./source./base_no.4757950/str_base_no.4757950%2C/header_title.Keyword+Search/page_name.search%2Fkeyword%5Fresults%2Easp/searc h_type.toe+plate/search_option.Exact/deptsearch./dept_id./dept_id_p./dept_name./dept_name_p./ShowImages.yes/sq.0/cont.1/intPgNo.1/redirect./qx/product.htm (http://www.speedwaymotors.com/xq/asp/strBase_List./hilt./source./base_no.4757950/str_base_no.4757950%2C/header_title.Keyword+Search/page_name.search%2Fkeyword%5Fresults%2Easp/search_type.toe+plate/search_option.Exact/deptsearch./dept_id./dept_id_p./dept_name./dept_name_p./ShowImages.yes/sq.0/cont.1/intPgNo.1/redirect./qx/product.htm)

Or what I learned on, which was just a long piece of square stock with two perpendicular pieces coming off. One moveable one fixed. You make the two "legs" long enough to reach the middle of the tire and cut them to points. After you scribe a line on both tires, you set them to the front of the tire measure it with a tape, then do the same in the rear of the tire. The difference is the toe. But the toe plates are nice because you don't have to crawl under the car and scribe the tires.

I just tied a straight-edge to each front tire with a bungee cord and adjusted for 1/16" difference between the front edge and rear edge.

I set camber with a $5 angle finder, and caster with a combo of the angle finder and a bubble level.

Checked for front to rear alignment with a piece of string.

When I drove it to the alignment shop and gave 'em the specs I wanted, it was well within tolerance. In fact, it was so close that it blew my mind!

The old guy that did the alignment told me that he started out using similar "instruments", so it wasn't that surprising to him. He was just surprised that anyone would think to do such a thing in this day and age.

The only real change was that he changed the specs slightly so the car would hold the proper alignment specs with my weight in the car (at rest). He said that's how he always does the performance cars. This was at Sears Tire & Auto Center, no less!

throw a couple hundred pounds of dead weight in the driver's seat (a friend will do- just don't call them "dead weight". call them "steering wheel attendant or something flattering like that") and break out the string and tape measure...