Do you know about curl/wget? Each one does pretty much the same thing as the other, but you can start a religious war by suggesting that one is preferable.
Anyway, either of them will let you mirror a website so you never have to worry about it going down.
And, since every Unix command line tool inevitably gets mined and turned into a web service, you could always submit those urls to archive.org instead of or as well as curl-ing/wget-ing them.