To co-incide with extending the VCP3 to VCP4 "upgrade" until the end of January 2010, VMware have also extended the 2nd-shot promotion for VCP4 until the same date. The promotion was originally launched at the start of October, and was supposed to run until the end of 2009 - I announced the promotion here.
Here's the all important dates:
January 15th 2010 = last day to register for the 2nd-shot voucher (before 5pm PST)
January 22nd 2010 = last day for 1st attempt at VCP4 exam if the free re-take is required
January 31st 2010 = last day for 2nd attempt at VCP4 exam using free re-take
Remember, if you need some help with the VCP4 exam, I run a VCP4 exam prep workshop which will maximize your chances of passing, 1st time or 2nd time! Global Knowledge UK are scheduling another workshop in London mid-January, email me for more information.