The way I see it, here are regulations that have effective dates that must be postponed -

E-Verify federal contractor rule (20 February 2009)
New I-9 form (effective 2 February 2009)

Quite a few rules had effective dates just before the new President took office. Yup - I'm sure that was just a big coincidence. In case you're interested, they are

ESTA  (January 12th)
US VISIT applicable to green card holders (January 18th)
H-2B (January 18th)
H-2A (January 17th)
Voluntary Departure (January 20th)
EOIR Attorney rules (January 20th)
T & U Rule (January 12th)
DNA collection (January 9th)
Diversity Visas (January 19th)
Visa Waiver Program for Guam and Northern Mariana Islands (January 16th)