Reformatting Chat Protocol?

[Felix E. Klee]

In a text file, I want to reformat a block as follows. Its a chat
protocol with various lines longer than the value of `fill-column'.

From:

  [11.11.2010 17:01:37] bla bla bla bla bla bla bla bla bla bla bla
bla bla bla bla bla bla bla bla bla bla
  [11.11.2010 17:04:21] bla bla bla bla bla
  [11.11.2010 17:05:25] bla bla bla

Into:

  [11.11.2010 17:01:37] bla bla bla bla bla bla bla bla bla bla bla
    bla bla bla bla bla bla bla bla bla bla
  [11.11.2010 17:04:21] bla bla bla bla bla bla bla bla bla
  [11.11.2010 17:05:25] bla bla bla

Or:

  [11.11.2010 17:01:37] bla bla bla bla bla bla bla bla bla bla bla
                        bla bla bla bla bla bla bla bla bla bla
  [11.11.2010 17:04:21] bla bla bla bla bla bla bla bla bla
  [11.11.2010 17:05:25] bla bla bla

Any simple solution?