Yes, you can have a website hosted on one server, while having a subdomain of the same site hosted on a different server. Here’s a quick how-to tutorial for accomplishing that.
mySQL command for closing all comments and pingbacks in WordPress installation; handy for closing comments on old server during hosting move. This also allows clients to easily check domain resolution.
Moving WP to a new domain? Beyond just moving the files, you’ll need to make a couple key database changes to make your new installation work properly.