There is no reason SKYPE shouldn't work. I have not tried it but will soon and report my experience.
I have similar icons on the samisite.com website for my availability on IM services (AIM, ICQ, MSN). When I am available, the icons on my contact page show that. I have set my IM services to require my acceptance/approval before allowing incoming events. Have NOT experienced increased spam or had a prblem and I have had those indicators on the site for a couple years now. If you have similar options to limit incoming calls with approvals, that should cut down on that issue.