You can now down­load the new msn mes­sen­ger beta (with­out an invi­a­tion). Basi­cally go to Microsoft’s Live web­site here, click on Win­dows Live Mes­sen­ger beta and then click on sign up and fol­low instructions.

I’m using this MSN Mes­sen­ger Beta right now and it has some new fea­tures like the abil­ity to send offline mes­sages (AT LAST!) and many more bells and whistles.