We have a thing called "Classlink 2000" which is basically what you're after, I think. However, to my knowledge, it's a piece of software that Viglen only supply to schools. Although, knowing Viglen, it's just another program re-branded to sound like it was designed for a school, so you might be able to find the original, if there was one. Alex would know more about it.
I'm not sure about that. You can install the ADMINPAK.MSI file from a domain controller to manage an AD domain remotely, but the glaring security issues over doing it with a web browser are not even worth thinking about.
Like I said - it can be a bit slow, and as Chris pointed out, security is a major concern. Letting people manipulate user accounts over the internet = bad, so you want to be damn sure that the right people are doing the right things.
Don't you bloody dictionary me, you barseless organ grinder. If I wish to run two words together to effect a stylishness which would otherwise be lacking, then I shall run two words together to effect a stylishness which would otherwise be lacking, and I'll smack you if you wince.
shakespeare said: "brevity is the soul of wit." i say: "wank." thus, i win.