This is something we've discussed at length over the last few months on another forum, as "ryanj" will no doubt recall.
Basically, the new Part P of the Building Regs. will mean that domestic installations in England & Wales will be required to meet a certain minimum standard for the first time. (Although IEE Wiring Regs. have been widely accepted as the norm until now, there has been no legal obligation to follow them.)
Compliance with the new regs. is supposedly going to be by one of two methods:
1. By the person installing the system becoming a registered installer and self-certifying his own work,
-- OR --
2. By giving notice of the intended works to the local council, paying them a fee, and having them come and inspect it.
Certain minor works are exempt from the requirements.
Here's a link which covers the basics:
http://www.iee.org/Publish/WireRegs/BR-PartP-dwellings.cfm
As a newcomer to this forum, I'm not sure what consensus of opinion has been reached here, but in our group elsewhere we've already pretty much come to the conclusion that the rules are badly thought-out, will be poorly implemented, and except for new builds and major renovations where an inspector is involved anyway, will be virtually unenforcable.
The more cynical of us see it as yet another one of this government's attempts to address some "problem" by introducing yet more bureaucracy and collecting more money.
By the way, I wrote my local council to ask what arrangements they have put in place for part P, how they would arrange inspections, and what the fees would be. With little over a month to go, I'm still waiting for a reply.
P.S. The following is a link to the full Approved Part P document from the website of the Office of the Deputy Prime Minister (PDF is about 1.4MB) :
Approved Document Part P
. I know it's to do with electrics having to comply with the building regs, and i have heard that it will come into effect as from January along with the new harmonized cable colours. But how will it effect electrical installers both approved and DIYers? 
