From the ITF: http://beta.itftennis.com/seniors/world-individual-championships/seniors/overview.aspx

The 2012 Seniors World Individual Championships will take place in San Diego, USA, from 12-19 February.  The fact sheet can be found by clicking on the Related documents link below.  Please note that the venue for the opening ceremony has changed and is now the San Diego Air and Space Museum.  Provisional start days for each event are as follows:

Sunday 12 February: MS45, MS50, MS55, WS50, WS55, XD35, XD40, XD45, XD50, XD55

Monday 13 February: MS35, MS40, WS40, WS45

Tuesday 14 February: WS35, MD35, MD40, MD45, MD50, MD55, WD40, WD50, WD55

Wednesday 15 February: WD35, WD45

Please note that these dates are provisional and may change.

The official tournament website can be found at www.itfsandiego.com.