On Skype: I've found that running our own IRC server and setting up ZNC* with accounts for all employees/developers has made a huge difference. The bonus for us is that since we do alot of open source work, it encourages developers to connect with other open source developers over IRC which is a great way to grow knowledge or get quick feedback for whatever framework/language/library we're working with at the time.
* http://en.znc.in/wiki/ZNC is a IRC bouncer that allows each user to keep their choice of clients, but still have catchup if they're offline.
I'd actually love to use IRC... but we're just not confident that it'd work well for the non-technical people, and we need them to be able to get into the project chats and demo chats.
There's a plethora of IRC clients available, many of them very easy to use. No, you do not need to be a genius to be on IRC. Administrating channels (/mode and such) is a bit harder, but not everybody needs to do that.
We're experimenting with IRC at MyEdu; while it hasn't been awful for non-technical users, it's not necessarily great either. The above-mentioned HipChat seems like it could be more viable, so I'm adding it to the candidate list.
EDIT: Not primarily for remote working, granted, but for quick collaboration and some dev-related announcements.
* http://en.znc.in/wiki/ZNC is a IRC bouncer that allows each user to keep their choice of clients, but still have catchup if they're offline.