Texas GOP state chairman Tina Benkiser announced at today's meeting of the State Republican Executive Committee that she will resign her post, effective October 5.  She is taking on the role of senior advisor to the Rick Perry for Governor reelection campaign.

I'll update as this develops.  The word spread via Facebook and Twitter feeds, as SREC members and attendees updated from the meeting.

Chairman Benkiser's Twitter update on the matter is here.  The Republican Party of Texas posted a press statement here.  The Rick Perry campaign posted a press release.

ETA:  An update on how Benkiser's successor will be chosen.  The SREC will vote on a replacement, although vice chairman Dr. Robin Armstrong may be a candidate for that.  According to the Texas Election Code:  

Sec. 171.003.  FILLING VACANCY.  (a)  The state executive committee shall fill by appointment any vacancy on the committee, including a
vacancy in the office of chair or vice chair.

The SREC reportedly has a rule that the vacancy must be filled in thirty (30) days.