The "Download Now" link directs you to the iTunes App Store, where you must continue the download process. You must have iTunes installed in order to open the link, and you must have an active iTunes account to download the application. This download may not be available in some countries.
Regexecution makes creating and testing regular expressions easier. It is a tool that allows you to reference, build and test regular expressions. Regexecution gives you functionality such as copying to clipboard, inserting operations directly into your expression and emailing all of your expression and test data to any email address.