I can send you the latest version of the software if you like, so you can have a look, just PM me your email address. I don't suppose Datalogit will mind as its not much use without the interface box.
I think its pretty good, easy to use and lots of good functions. The graphing ability is a bit basic though, so I normally export things to Excel and plot them with that instead. Apart from that its fine.
To answer your question, yes, you can share the software, have it on as many computers as you like, but you will have to share the interface box.