On a Mac, old iPhone/touch applications are moved to the Trash. If you want to the old version back, drag the old version out of the Trash. Locate the currently installed version in the "Mobile Applications" folder (right click on the application icon in iTunes and choose "Show in Finder"). Drag this file to the Trash. Quit iTunes (just to be sure). Move the recovered application file to the "Mobile Applications" folder and double click it to reopen iTunes. Now... it should load the old application version.
The process should quite be similar on a Windows machine.
This didn't work due to the fact that I no longer have 1.0 from all the times I tried to delete, then install fresh.
I am able to now download it to my Mac in iTunes, but when I check mark to sync Apps' it SAYS it's on my iPhone, but it's not.
Other apps download and install just fine.