Field mapping define which Salesforce and Outlook fields correspond when records sync with Salesforce for Outlook.  Salesforce comes with a set of default mappings.  You may be able to change some of them.

To map fields:

1. Click Your Name | Setup | Desktop Administration |  Outlook Configurations.
2. Under Data Settings, click Edit Field Mappings to display the list of available fields.
3. Choose a field from the Salesforce Field picklist.  This list displays the names of all Salesforce fields that haven't yet been mapped.
   • WARNING: If you map a custom fields that is universally required, make sure it has a default value to avoid errors.  Also, note that mapping custom fields that require validation by Salesforce may cause sync errors.  For example, if you map a custom Salesforce field that requires a unique value, you'll get a uniqueness error when you sync if you enter a non-unique value in the Outlook field.
4. Choose a field from the Outlook Field picklist next to the selected Salesforce.com field.  This list displays the names of all standard Outlook fields that haven't yet been mapped and that match the data type of the corresponding Salesforce field.
5. To map a Salesforce field to a custom Outlook field, select Custom Fields...from the end of the corresponding Outlook Field picklist.  Enter the field's name and click Okay.
   The custom field must already exist in Outlook. Letters are not case-sensitive, and these characters aren't allowed: [,], _, #. The first sync validates that the custom Outlook field exists and then maps it to the Salesforce field. Custom Outlook fields use a string data type. Note that we only allow custom fields for Salesforce text fields and non-restricted picklists.
6. To remove a field mapping, click the delete icon to the right of the mapping.  To redo the mapping, just add a new mapping to the bottom of the list.  To view your mappings, click View under Field Mapping on the detail page.
7. Click Save.  All changes take effect the next time data syncs for the users in this configurations.
   • Please note, you can map custom Salesforce fields to standard or custom Outlook fields.  You can't map picklist values.