Excel links for you...

                                                              MS - Excel :

Official Excel Microsoft Blog:
http://blogs.office.com/b/microsoft-excel/

Basic Excel training in Microsoft office blog:
http://blogs.office.com/b/microsoft-excel/archive/2011/06/28/take-the-next-steps-in-growing-your-excel-skills.aspx 

Excel Archive Forums
http://www.mrexcel.com/archive/index.html 

Writing Macros:

http://office.microsoft.com/en-us/excel-help/CH010369017.aspx?9656

Vlookup information:
http://vlookupweek.wordpress.com/ 


Vlookup Example:

http://colinlegg.wordpress.com/2012/03/25/binary-searches-with-vlookup/ 

updating prices in master list using vlookup:
http://blogs.office.com/b/microsoft-excel/archive/2012/03/28/-vlookup-tutorial-from-bill-jelen.aspx 

Counting Unique values / Text with out duplicating text items:
http://office.microsoft.com/en-us/excel-help/count-unique-values-among-duplicates-HP010070481.aspx?CTT=3 

About Frequency:
http://office.microsoft.com/en-us/excel-help/frequency-function-HP010062503.aspx?CTT=5&origin=HP010070481 

Match:
http://office.microsoft.com/en-us/excel-help/match-function-HP010062414.aspx?CTT=5&origin=HP010070481 

Holding control to enter data automatically in other sheets:
http://office.microsoft.com/en-us/excel-help/enter-data-manually-in-worksheet-cells-HP001216364.aspx 

to count the duplicates  =countif($A:$A,A1)
http://answers.yahoo.com/question/index?qid=20081114050312AAYxL2y 

To add name kumar in the end use concatenate:
CONCATENATE(E13,"kumar")
http://stackoverflow.com/questions/2703431/add-common-prefix-to-all-cells-in-excel 

IF examples:
http://office.microsoft.com/en-us/excel-help/if-function-HP010342586.aspx?097 

Forumula's in Excel:
http://office.microsoft.com/en-us/excel-help/excel-functions-by-category-HP010342656.aspx#BMcompatibility_functions 

Avoiding Duplicates: Error message, before saving the workbook:
Source:
http://excelzoom.com/2009/05/data-validation-to-avoid-duplicate-values/

Click Data | Validation.

On the Data Validation window’s Settings tab, select Allow: Custom.

In the Formula box, type the following formula: =MATCH(A1,$A:$A,0)=ROW(A1) (if you’re using this in a different column than column A, change the “A1″ and “$A”‘s in the formula to whichever column you’re using)

Click OK.

Adding List drop down using data validation:
Source: 
http://excelzoom.com/2009/03/drop-down-lists-using-data-validation/

To do this, follow the steps below.

• Select the cell where you want your custom list to appear (if you want the same list to appear in multiple cells, you can copy the list later).
• Click Data | Validation.
• On the Data Validation window’s Settings tab, select Allow: List, and make sure the In-cell dropdown box is checked.
• In the Source box, type the items you want in the drop down list separated by a comma. Alternatively, you can refer to a range of cells in the same worksheet that contains your list, or refer to a named range elsewhere in your workbook.
• Click OK.

Pivot tables examples:

http://excelzoom.com/2009/03/using-pivottables/

http://www.pivot-table.com/
www.free-training-tutorial.com 
www.homeandlearn.co.uk

Consolidate example: 
http://blogs.office.com/b/microsoft-excel/archive/2012/07/05/merge-worksheets-in-excel.aspx

Recording Macro:
http://excelzoom.com/2009/02/install-and-use-macros/

Automatically creating Index for files:

http://excelzoom.com/2009/03/automatically-create-an-index-for-your-excel-file/

Common Formula's in Excel:
http://office.microsoft.com/en-us/excel-help/CH001000491.aspx

Hiding formulas or locking cells:
http://office.microsoft.com/en-us/excel-help/display-or-hide-formulas-HA102430137.aspx

VBA & Macros


http://www.excel-vba.com/excel-vba-contents.htm

http://msdn.microsoft.com/en-us/library/office/ee814737(v=office.14).aspx

http://www.ozgrid.com/VBA/

http://www.functionx.com/vbaexcel/Lesson02.htm

http://www.ehow.com/excel-vba/

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