This article might of interest to you, if you're planning to change your existing domain or already in the process of shifting to a new domain. In that case, there’s few things that require changes in the different Google apps.

• Add the new domain in your AdSense channels
  Choose AdSense -> AdSense Setup -> Channels -> URL Channels -> Add new URL channels
• Change your reply-to address in Gmail, if you used a redirect
  Choose Gmail -> Settings -> Accounts -> Edit info
• Change your signature in Gmail, if you used the old domain name in it Choose Gmail -> Settings
• Add your domain into the Google Webmaster Tools
  Choose Google Webmaster Tools -> Add Site (you then need to verify your site by e.g. uploading an HTML file)
• Tell Google Webmaster Tools your preferred domain, and allow advanced image functionality
  Choose Google Webmaster Tools -> [your domain] -> Preferred domain/ Enhanced image search
• If you’re using the AJAX Search API, generate a new key to work with your domain
  Choose Google AJAX Search API -> Generate API Key
• If you provide a “site:yourdomain.comâ€? search somewhere, adjust it accordingly
• If you have a blogger profile, change your homepage settings
  Choose Blogger -> Edit Profile -> Homepage URL
• Update your Google Groups profile with the new domain
  Choose Google Groups Profile -> edit -> Website or Blog
• If the iGoogle gadgets you hosted stop working...
  Resubmit each of your gadgets to the directory. Then submit an alias request with Google for each of them. (... I’m still checking how this will work out)
• If you have an Orkut profile, change your homepage Choose Orkut -> profile -> edit [the second from the top] -> webpage
• Tell YouTube your new homepage
  Choose YouTube -> My Account -> Personal Info -> Website URL
• If your site is indexed in Google News, alert Google support of the change
  Try emailing source-suggestions@google.com (still testing this)
• Check if you have any Google Alerts where you do URL searches
  Choose Google Alerts -> manage your alerts [you may not always see all alerts this way, unfortunately]
• Tell Google Analytics your new domain
  Choose Google Analytics -> Edit [in the site’s row] -> Edit -> Website URL
• If you have any AdWords campaigns running, change the domain you’re advertising
  Choose AdWords and check your campaigns

Source:? Blogoscoped

Google, Google Apps, Domain, Moving Domain