This website gives links to the most common notifications:
http://www.usa.gov/Citizen/Services/Change-Of-Address.shtmlIf you live in a state (Virginia is a prime example) that tries to hold onto you forever for state income tax, there are a number of things you
may want to do.
If you sell a vehicle, and KEEP records of the sale; if the state DMV requires that you turn in the number plates, keep the receipt.
Report a change of address for your driving license; some states don't care, some will cancel a license if you move out-of-state. Your state MAY have a rule that requires you to report any change of address within 30 days; if you don't, the license may be invalid by default. Caution here - you can drive in the UK for up to 12 months on your US license, but only if that license is valid. Again - keep the paperwork.
Report a change of address to the local board of elections. You are still entitled to vote by absentee ballot in Federal elections, but this is one of the things that indicates intent not to return to your current state of residence.
Write to the state department of taxation (if you have state income tax) and inform them that as of XX date, you became non-resident, and stress that this is a permanent move out of the state. Make sure you understand your income tax filing status for the year you move and subsequent years, if applicable.
There is a form to notify the IRS, but most of us just use the new address when filing a tax return. See
http://www.irs.gov/pub/irs-pdf/f8822.pdf