Windows Live Messenger 8.0 is currently in the closed beta testing stage. That is, only people that are approved by Microsoft (either being selected directly by Microsoft or being invited by others) have access to .net Messenger service with Windows Live Messenger 8.0.
For those who are not the testers, there do exist ways to sign in with WLM 8. However, such ways are
illegal (for example, hacking/cracking into Messenger executables). The
forums rules do
not allow illegal contents, and hence, please do not post about anything about how unauthorized people can get access to the closed beta or sign in with it. This includes but not limited to: posting about where to download the beta, how to hack/crack into the service and of course, links to them. Please do not challenge the rules, or, we all know, you get banned. Thanks for cooperation
Feel free, though, to look for invites for legitimate use of Windows Live Messenger
(But only in Testing & Trashing) .