SharePoint 2010 Lists support Field Validation which enables you to validate the values. Field Validation allow you to “specify the formula that you want to use to validate the data in this column when new items are saved to this list. The formula must evaluate to TRUE for validation to pass. “
Example: If your column is called "Company Name" a valid formula would be [Company Name]="My Company".
To Test out the Validation go to the List and Select List from List Tools