Actually, i do know that the protocol hotmail uses, usually called httpmail, is nothing more than a set of http/1.1 extensions generally called WebDev.. so it is not propriatery, it just seems to be that no one else supports it.
I was hoping that someone knew a program for linux that does. Unfortunately for me, I have little choice but to use the msn/hotmail servers, as i do tech support for msn.... it sucks but it is a job..... and i sometimes need to see what is in my 2 mailboxes before i go into work. I just didn't want to take the time to log into hotmail 2 times each morning.....