Calendars, Calendars

Hello everyone. First post here, so hi, how ya doin, etc.

I have a dilemma at work that needs solving. It has to do with a calendar program that we rely on but is run on ancient software made by a now-defunct company. The "server" portion runs on NT4 Server. Yeah, it's that bad.

Now, what I was looking for is perhaps some solution tips. Here's what it needs to do:

Have localized non-networked support (ie, offline mode)

Have synchronization support (I come in after 2 weeks away, synchronize the new events and upload my changes to the calendar as well)

Have OSX Support (we're primarily a Mac shop...by 1-2 computers).

Now, if that wasn't tough enough, I'm trying to think of a way to do this without disrupting their current workflow as they're used to it. Basically, since their existing program is Mac-only, I've been very interested in iCalendar. It conforms to a nice standard, is usable in a variety of programs (including those of the Windows variety), its free, its included with OSX, plus it is easy to use and with the help of iSync shouldn't be too bad to implement.

However, iSync tends to reference its own challenges, not to mention user training (total employees: just 11), and I'm curious to hear ideas. I've looked into Exchange as well, but most of us here have dealt with these sorts of problems, and I'm just trying to find out what works. Don't worry about the financial burden, if I find the right solution that will last us a long time, I'm willing to stick my neck out and push for that one. Something more than "just use Exchange!" will be most appreciated.

Evan