How to create a pdf form others can fill out and email back to me.

With Acrobat Standard or Professional you can apply 'Extended Reader Rights' so users with Reader before version XI and fill-in and save the forms if they have Reader 6 or better.

Be sure to read the ELU because you are limited to 500 return forms using this method and above that you should contact Adobe about licensing a LiveCycle server to apply the special rights for Reader.

You can avoid the above if you submit the form to a scripted web page for any additional processing.