In an update at Wondercon, IDW's head editor Andy Schmidt announced that from July until the end of the year, Transformers will become a bi-weekly comic release!  Here is the full schedule he announced:

JULY 2011
Transformers # 21: Prelude to ChaosWritten by Mike Costa, art by Guido Guidi and Brendan Cahill.
Transformers # 22: Chaos Theory Part 1Written by James Roberts, art by Alex Milne.

AUGUST 2011
Transformers # 23: Chaos Theory Part 2Written by James Roberts, art by Alex Milne.
Transformers # 24: Chaos Part 1 Story by Mike Costa and James Roberts, art by Livio Ramondelli.

SEPTEMBER 2011
Transformers # 25: The Last Earth Story Part 1 Written by Mike Costa, art by Brendan Cahill.
Transformers # 26: Chaos Part 2 Story by Mike Costa and James Roberts, art by Livio Ramondelli.

OCTOBER 2011
Transformers # 27: The Last Earth Story Part 2 Written by Mike Costa, art by Brendan Cahill.
Transformers # 28: Chaos Part 3Story by Mike Costa and James Roberts, art by Livio Ramondelli.

NOVEMBER 2011
Transformers # 29: The Last Earth Story Part 3 Written by Mike Costa, art by Brendan Cahill.
Transformers # 30: Chaos Part 4Story by Mike Costa and James Roberts, art by Livio Ramondelli.

DECEMBER 2011
Transformers # 31: Chaos Epilogue Written by Mike Costa, art by Casey Coller.

You can listen to the announcement here at theterrordrome.com