You can find Mikael Renberg's own blog on Swedish Radio's homepage.

Mikael Renberg's blog on Swedish Radio (in swedish)

He blogs about the NHL premiere in Stockholm and he think it was a pretty mediocre premiere.

There are also several rumors regarding his comeback. Malmö, Linköping, Skellefteå and even Luleå has been talking to him according to press rumors.

Edit: I just saw that one of Renberg's blog entries is about that comeback. He pretty much denies it.

Edit: Renberg will make a comeback, but it is in a veterans game tonight in Helsinki, Finland v a Russian team containing amongst others Igor Larionov. Source