How do you read XML column in SQL Server 2008?

Try something like this:

SELECT
   Cust.value('(ItemId)[1]', 'int') AS 'ItemID',
   Cust.value('(Value)[1]', 'Varchar(50)') AS 'Customer Name'
FROM
   dbo.Sales.CustomerList.nodes('/ArrayOfCustomers/Customer') AS AOC(Cust)

That should give you an output something like this:

ItemID  Customer Name
   1         Mr Smith
   2         Mr Bloggs

You need to use CROSS APPLY from table to XML column

create table sales (customerlist xml)
insert sales select '
    <ArrayOfCustomers xmlns:xsd="http://www.w3.org/2001/XMLSchema"        
                      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
       <Customer>
           <ItemId>1</ItemId>
           <Value>Mr Smith</Value>
       </Customer>
       <Customer>
          <ItemId>2</ItemId>
          <Value>Mr Bloggs</Value>
       </Customer>
    </ArrayOfCustomers>'

Your query:

SELECT
   N.C.value('ItemId[1]', 'int') ItemId,
   N.C.value('Value[1]', 'varchar(100)') Value
FROM dbo.Sales
CROSS APPLY CustomerList.nodes('//Customer') N(C)

EDIT - note
The query above was written quickly to illustrate working with xml columns in a table (multi-row). For performance reasons, don't use '//Customer' but use an absolute path instead '/ArrayOfCustomers/Customer'. '//Customer' will go through the entire XML to find Customer nodes anywhere in the XML at any level.