can I run a .68A motor ?

I plan to build the motor shield http://www.ladyada.net/make/mshield/

but the specs say it can only handle .6 A for a stepper

I only plan to run 1 motor total.. I would like to run this one: http://www.robotshop.us/rbsoy14-soyo-un ... motor.html

but it draws .68A

think it would be OK ?

If it's relatively unloaded, put an ammeter on it to see how much current is actually being drawn during use.

You can get a DIP heatsink to help the LM293D chips run a little cooler.

Or try the time honored thing and stack the chips to double your current capacity. It's mentioned on the LadyAda webpage http://www.ladyada.net/make/mshield/use.html as follows:

Need more power? Buy another set of L293D drivers and solder them right on top of the ones on the board (piggyback). Voila, double the current capability!

the specs say it can only handle .6 A for a stepper

I would like to run this one: but it draws .68A

If the spec says the absolute maximum is 0.6A then that's it. It's like trying to put a 6' wide car in a garage that is only 5' 11.5" wide, it's a no go. In fact in engineering terms if the spec says 0.6A they I would be reluctant to put any more than 0.5A through it.