On the Unofficial Wolfmother Forums, alot of ruckus and slander was put across when member “dingdongding” signed up to inform everyone that Chris and Myles were to split after Wolfmother played at Splendour In The Grass Festival at Byron Bay last weekend (Aug 2-3).
Her accusations were tossed aside along with her very cocky attitude, but perhaps there is merit to her “news”.
On February 8th, The Age’s lift-out “EG” had a very small article with this to say:

As for Wolfmother, we hear drummer Myles Heskett and bassist Chris Ross have been jamming together without singer Andrew Stockdale.
Are they just enjoying a break from the Mother or starting a new band?

Still not confirming any break-up though… Until now.
On August 4th, triple j’s music news had this article posted on their site:

Wolfmother line-up change after Splendour?
Wolfmother tore up the main stage for perhaps the last time with their present line up to close Splendour in the Grass 2008… watch this space for more. Richard Kingsmill talked to the band before they took the stage, and they delivered him this unexpected new twist.

Dingdongding seemed pretty smug on the forums when that was posted.
However, there was rumour of an extra guitarist joining the band early last year.
As of yet we have no confirmation to the rumours, but keep watching this site for any more goss.