charlier - 1:56 pm on Oct 25, 2005 (gmt 0)
One small point about using 301, if you are making other changes to the site you may wish to wait untill those changes have been spidered before you add the 301. We had a problem with duplicate content for a .com and .co.uk site, we lost about half our google referrers over a two week period with the .com pages just disappearing. We decided to change all the URLs in the site to absolute URLs using the .com domain name; we also added a 301 from the .co.uk to the .com and we set up a little script to monitor what domains google was spidering. To our chagrin we found the googlebots were only spidering the .co.uk domain and not picking up the new pages at all, they were just getting the redirect URLs and leaving. To make a long story short we took out the 301 and over the next two weeks google respidered all the pages (>50,000) and we completly recovered in the index. Now we can put the 301 back and hopefully the problem will not recur.