Re:Big Nasty Guys With Guns (Score 3, Informative)

A printout should be fine according to the FTC:

The "clock" on your obligation to ship or take other action under the Rule begins as soon as you receive a "properly completed" order. An order is properly completed when you receive the correct full or partial (in whatever form you accept) payment, accompanied by all the information you need to fill the order.

http://www.ftc.gov/bcp/conline/pubs/buspubs/mailor der.htm