Micro Anvika will be selling Mac OS X at midnight on March 24 at its Tottenham Court Road branch in London.
The store will open at 11pm on Friday, March 23.
Gary Young, Micro Anvika's director of purchasing, points out that Apple Store customers are unlikely to receive copies of OS X before the following Tuesday. The store is promising special offers, and incentive give-aways on the night. Mac OS X will cost £84.
Apple Centres and resellers worldwide are also organizing events to mark "OS X-Day". In the UK, expect to see demonstrations and in-depth tutorials at various Computer Warehouse locations and at Tasha in Kensington, London.
Outside London, Apple Centres in Brighton, Southport, Hull, Edinburgh and Glasgow have already confirmed plans to run special OS X days. The Apple Centre Sheffield will be hosting a "Big Mac Day", with demonstrations, a chance to see a 733MHz Power Mac G4, and able assistance from the Yorkshire Macintosh Users Group.
It's believed that special demo days will also be held in Cardiff, Gloucester, Cambridge, Oxford, Stockport and Nottingham. Many other retailers are also planning events to commemorate the launch.
Mac OS X is expected to ship pre-installed in all Apple computers from July.