Oki.. registered just to add to this thread and belay a few of the typical apple hater BS that people spout.
Plus, Winamp and uTorrent:
Not yet; more than enough projects exactly the same; umm its been around for ages.
With OSX Snow Leopard the application interaction is greatly improved but on multiple layers within the system based upon the settings of the application itself. E.g: you can pull an itunes song into ANY program by calling the itunes library class within the host program and without iTunes having to be open or running.
So yes, you could do exactly what plus does on windows with the mac provided its running at least leopard OS.
For all of you though that think it would be oh so simple to build a program as complex and established as msgpluslive for the Mac and instantly make it as good as the windows version, then i'm sorry to tell you that you're gonna be disappointed.
Just ask any software provider that wrote for Windows exclusively then branched out to mac, either the software takes too long to write to the current windows version, or you release a very very cut down version for the mac and lose your customers before you start.
If you want MPL for the mac, then you'd be better off starting from scratch all over again and building up like patchou did with the windows version. I can see exactly why patchou has said buy me a mac and i'll try, and why he hasn't gone out already and tried. If you have a winning formula, don't mess with it.
I've been a programmer in windows for years, I moved to macs because of my own reasons and because of the graphical and audio manipulation and i've tried writing simple things like iPhone apps... Its not as easy as it sounds even for someone with 10 years experiance writing C++ code!!
What would be easier would be to find a seasoned apple programmer, get him/her and patchou in a room together and let them figure out what parts of MPL would work and go code them out in a whole new program.
p.s: sorry to piss on dreams, but just trying to be realistic from a programmers p.o.v.
p.p.s: Hi everyone!!
newbie to the board