Using Apex Variables in SOQL and SOSL Queries (SOQL IN Clause)

I spent some time looking for this documentation around using the SOQL IN clause with a list and wanted to save it.

I basically want to run a SOQL query that is looking at a list of String values in the WHERE condition, like this:

// An IN-bind with an Id list. Note that a list of sObjects
// can also be used--the Ids of the objects are used for 
// the bind
Contact[] cc = [SELECT Id FROM Contact LIMIT 2];
Task[] tt = [SELECT Id FROM Task WHERE WhoId IN :cc];

// An IN-bind with a String list
String[] ss = new String[]{'a', 'b'};
Account[] aa = [SELECT Id FROM Account 
                WHERE AccountNumber IN :ss];

http://www.salesforce.com/us/developer/docs/apexcode/Content/langCon_apex_SOQL_variables.htm