General Excel Sites:
One of our favorite Excel web sites, full of tips, articles, sample spreadsheets and templates. Always worth a visit. Excel consultancy services available.
Excellent resource providing alternative and imaginative solutions to Excel problems . Suitable for intermediate and Advanced users. Andy also has many solutions for PowerPoint problems.
This site by David McRitchie is a treasure strove of Excel articles and solutions. Well worth a visit by anybody interested in Excel.