Here is the methodology for getting to the account picklists (but it works with pretty much any entity).

ExportXmlRequest exportRequest = new ExportXmlRequest();

exportRequest.ParameterXml = @"<importexportxml>

                                          <entities>

                                                <entity>account</entity>

                                          </entities>

                                          <nodes/>

                              </importexportxml>";

ExportXmlResponse entities = (ExportXmlResponse)service.Execute(exportRequest);

Now you will have string containing the Account ImportExport.xml. Load this into a XML document.

Now parse throught the Attributes element looking for picklist attributes:

            <attribute PhysicalName="PreferredContactMethodCode">

              <Type>picklist</Type>

              <ValidForCreateApi>1</ValidForCreateApi>

              <ValidForUpdateApi>1</ValidForUpdateApi>

              <ValidForReadApi>1</ValidForReadApi>

              <DisplayMask>ValidForAdvancedFind|ValidForForm|ValidForGrid</DisplayMask>

              <Description>Preferred contact method for the account.</Description>

            </attribute>

The actual picklist values are in the FieldXml element (not in the attributes - this is the trap for young players).

            <field name="preferredcontactmethodcode" requiredlevel="na" defaultvalue="1">

              <displaynames>

                <displayname description="Preferred Method of Contact" languagecode="1033" />

              </displaynames>

              <options nextvalue="7">

                <option value="1">

                  <labels>

                    <label description="Any" languagecode="1033" />

                  </labels>

                </option>

                <option value="2">

                  <labels>

                    <label description="E-mail" languagecode="1033" />

                  </labels>

                </option>

                <option value="3">

                  <labels>

                    <label description="Phone" languagecode="1033" />

                  </labels>

                </option>

                <option value="4">

                  <labels>

                    <label description="Fax" languagecode="1033" />

                  </labels>

                </option>

                <option value="5">

                  <labels>

                    <label description="Mail" languagecode="1033" />

                  </labels>

                </option>

              </options>

            </field>

Now you can edit these values here and then re-import the data back to CRM the ImportXml and Publish web service messages.

Hint: don’t get distracted by the languagecode …. these are not the droids you are looking for.

        <Icon type="GridIcon">R0lGODlhEAAQANUzAP//s9nYh7+/fc/Pj9CkG9TJe//3n8+iG//xl/TQcPXsqc/HfM/PhP/+4///9f/Vcf/90tnZpc/Kf7+/if/8vcTEj9nZl//qjenLcdnZiP/de//6pNTFd8nJi9TPgf/Qat/fqunYftCkF//WcKmpc//geru5rP/9l//Ra//1j//uiNmmGv/ogv//8v//33l3a9KkEv//mf//zP///wAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAACH5BAEAADMALAAAAAAQABAAAAaNwJlwSCwKYcikUmmawRytqHTagr2cDZd2y3VZnRCZODKpgMTiL4wCAHRIgwHJ0gaoN7EYI5MXCPIxagYnhIQBJAGFaggpjSkSJB6OKWoXKpcqJAuYl2osn58FIaCfaholqCUkHKhKVzAPI7IjGAmyMAoEL00wHyi/wL8wIrtHK8fIyAfFQiYvz9DRTUJBADs=</Icon>

      </Icons>