I am the webmaster for the band Estradasphere, and their website is currently hosted on godaddy. It makes me cry a little bit, it's true. Anyway, I want to move them to Linode, but I need to know one thing first.

They have a mailing list of 5500 email addresses. All of them have opted in, via signing up at a show or using the online mailing list form. Once or twice a month, they need to send 5500 email messages to people who have all requested them (no spam, seriously).

Is there anything stopping me from installing phplist on a linode and firing off 5500 email addresses?

Nope. There are no limitations at all other than your bandwidth quota and the Terms of Service, and in this situation it's very unlikely that you'd run into problems with either of them.

One thing to remember is that your assigned IP may have been previously used. Just make sure that your IP isn't on any RBLs or your mail might be marked as spam.