ShareMouse website is not available today when I tried a download.
I'm quite interested in checking this out, especially as I tried the ridiculous MS Mouse Without Borders thing last week.
Mouse Without Borders is a horrible FAIL at best. It totally relies on MS WorkGroup networking, which has always been crap. There was no way I could get two computers to connect through a desktop switch, even though they could ping each other. Because of the switch, they couldn't grok each others Computer Name and so wouldn't talk. Totally not workable for here at work, which is where I have the real requirement. Might work for a home setup.
I'm interesetd to find out if ShareMouse uses something modern like an IP address rather than old MS horsecrap networking models.
I'll continue to try the site today, to see if it comes back up. DonationCoder may have killed it! (which would be a good sign)