These are all links to information sites that I've found very useful.

Forums & Usergroups

1. VBAeXpress.com:
   
   1. VBA specific help for all office applications
2. JMT Excel Q&A Board:
   
   1. 100% Excel and Excel specific VBA
3. OfficeArticles Forum:
   
   1. A sub forum dedicated to every office application!
4. Excel User Group:
   
   1. A site dedicated strictly to all things Excel.
5. MrExcel.com:
   
   1. Mainly Excel and Excel specific VBA, some Access as well.
6. Tech Support Guy:
   
   1. The business applications forum support virtually all business applications.
7. Tek-Tips:
   
   1. There is a help forum here for virtually everything
8. UtterAccess.com:
   
   1. Mainly Access focussed, but some other applications as well.

Excel Blogs

1. The Ken Puls Blog
   
   1. Okay, it's a shameless plug, but this is my own blog, which serves as my testing ground for Excel related material, among other things.
2. Andrew's Excel Tips
   
   1. Andrew Engwirda's Excel Blog
3. Daily Dose of Excel
   
   1. Dick Kusleika's Excel Blog
4. .Net & Excel Blog
   
   1. This is Dennis Wallentin's new blog with a very specific focus on .Net and Excel
5. Methods In Excel
   
   1. Ross McLean's Excel Blog
6. Smurf on Spreadsheets
   
   1. Simon Murphy's Excel developer's blog

Reference Sites I Use

1. Anne Troy's Office Articles
   
   1. Anne has over 230 articles and tutorials available for the MS Office suite! Well worth the read!
2. Andy Pope's "AJP Excel Information"
   
   1. Andy's site is very heavy on Charts, with lots of great pictures and examples. He's also got a collection of Excel based games as well.
3. Bob Phillips xlDynamic
   
   1. Bob's site contains very comprehensive papers on Excel formulas and VBA. My personal favourite is his explanation of Multiple Condition tests using Sumproduct.
4. Chip Pearson's Excel Information
   
   1. Chip has an incredible amount of information on his site, including using the Windows API to get at things not accessible through VBA alone.
5. Colo's Junk Room
   
   1. Colo has all kinds of neat things at his site, including a Class Module tutorial, and tips for teaching VBA programmers how to program in javascript.
6. Dennis Wallentin's ExcelKB
   
   1. Dennis's site covers pretty much every flavour of VB that you can think of, Excel, Lotus Notes and databases. He has a great variety of KB articles and is well worth the visit.
7. Ivan F Moala's Xcel Files
   
   1. If it can't be done in Excel, Ivan will have an example of how it can... A site full of truly amazing information and undoubtedly bookmarked by every Excel developer.
8. Jan Karel Pieterse's JKP-Ads
   
   1. Jan Karel Pieterse is the author of the Name Manager and a MS Excel MVP.
9. John Walkenbach's Excel Information
   
   1. Author of the Excel VBA Power Programming series... a MUST have book for any aspiring VBA programmer!
10. Jon Peltier's Site
    
    1. Jon's site is the first place I look if I need to know how to do somthing with Charts in Excel.
11. Mark Rowlinson's Code Net
    
    1. Mark has some great articles including coverage of Visual Basic, Office and Web programming. My particular favourite is his tutorial on Passing arrays to and from functions
12. MVPs Excel sites
    
    1. The above is the direct link to the MVPs.org Excel site listing. It lists all of the Excel MS MVPs and alumni sites
13. Ron de Bruin's Excel Pages
    
    1. If you need to know something about sending email from Excel, this is the place to go. If you're looking for Outlook, Outlook Express or CDO, Ron has examples.
14. Russell Proctor's Better Solutions
    
    1. Russell has an ever growing site with a host of information for Word, Excel and powerpoint.
15. Stephen Bullen's Office Automation
    
    1. Stephen Bullen is one of the true Guru's of Excel, and co-author of Professional Excel Development, among other things. His site has some great utilities available for download.

Recommended Addins and Tools(all free!)

1. ASAP Utilities
   
   1. ASAP utilities is a standard install procedure for many advanced Excel users. Another addin full of great stuff!
2. Dave Brett's Duplicate Master
   
   1. Dave's addin contains tools to quickly highlight, or delete duplicate data from lists, and can also extract unique items as well.
3. HTML Maker
   
   1. Colo and Ivan's HTML maker has been used throughout this site to post interactive examples of Excel sheets. It was orignally designed for posting on messageboards.
4. MZ Tools
   
   1. If you do any VBA developing, you need this addin. It is loaded with useful tools such as a code reviewer and much more to speed up your development process.
5. Name Manager
   
   1. Jan Karel's name Manager is an essential add-in for working with names.
6. PDF Creator
   
   1. A free PDF writer utility that supports VBA.
7. Smart Indenter
   
   1. An awesome little add-in that makes indenting all of your code very simple. I find it really helps to know if you have an issue in a Case or If block, among other things.
8. JMT Utilities (formerly Andrew's Utilities)
   
   1. JMT utilities is just full of items to extend the functionality of Excel.