As of midnight last night the Bush Administration's window for passing rules and having them take effect before the Obama Administration takes office passed.
The rulemaking process, as established in the Administrative Procedures Act, states that all rule stake effect within 60 days of their establishment. Within 60 days (30 if the rules has lees than a $100 million impact on the economy) public comment can be offered that can have an impact on the proposed rule.
Here's a bit from Yahoo News discussing whether the rules are reversible:
Getting rid of a rule that is already in effect is enormously difficult, because it must be replaced with another rule. That process can take months or even years and could leave some of the Bush rules in place in the meantime. It can also lead to lawsuits.
“If you start the rulemaking process over again, the end product is likely to be challenged in court by somebody, and the administration would need to develop a record that supports the decision to promulgate a new rule,” said Robert Glicksman, an administrative law professor at the University of Kansas.
Bush’s midnight regulations also could be challenged by public interest groups, who are already considering legal actions to get some of them overturned. If the Obama administration agrees with the group’s position, it could promise the court to develop a new rule that both parties can agree on. But that would open up the possibility of further legal challenges from third parties, such as utility companies or other industry interests, which could assert that the Obama administration and the group were participating in a “collusion of interests” without adequately considering the impact on industry.
“By intervening, industry could buy more time and save billions of dollars by avoiding compliance to a new rule,” said Rena Steinzor, a University of Maryland law professor who is also a member of the Center for Progressive Regulation, a Washington, D.C.- based advocacy group.
Leave it to Congress to bypass such an arduous process, some Democrats in Congress are contemplating the use of the Congressional Review Act, an obscure Clinton-era law that allows Congress to vote to disapprove any rule finalized within about six months before Congress adjourns. It was passed by the Republican-dominated House in 1996, partly because Republicans wanted to shoot down Clinton-backed rules.
Here are links for more background:
From ProPublica: A masterlist of proposed regulations.
From the LAT: Environmentalists upset over some rules.
From Market Watch: Teamsters concerned about change in rules regarding hours truckers can drive.
From OMB Watch: Limits placed on use of Family and Medical Leave Act.
From ProPublica: Can Obama Reverse Rules?