This sample sets and gets the label and description for a cloud service.

LabelDescription.ps1

Set-AzureService -ServiceName leasetest2 -Description "This cloud service contains all frontend VMs, which are grouped into two availabilty groups." -Label "Frontend West EU"

<# Output

OperationDescription                             OperationId                                      OperationStatus                                 
--------------------                             -----------                                      ---------------                                 
Set-AzureService                                 54a6c394-f6d5-5d14-9496-ddaa1ad9076c             Succeeded                                       

#>

Get-AzureService -ServiceName leasetest2

<# Output

ServiceName             : leasetest2
Url                     : https://management.core.windows.net/c6264819-a8d6-4279-b493-4a47f4300c54/services/hostedservices/leasetest2
Label                   : Frontend West EU
Description             : This cloud service contains all frontend VMs, which are grouped into two availabilty groups.
Location                : West Europe
AffinityGroup           : 
Status                  : Created
ExtendedProperties      : {[ResourceGroup, leasetest2], [ResourceLocation, West Europe]}
DateModified            : 07.01.2015 21:23:13
DateCreated             : 08.12.2014 11:48:29
ReverseDnsFqdn          : 
WebWorkerRoleSizes      : {}
VirtualMachineRoleSizes : {}
OperationDescription    : Get-AzureService
OperationId             : c3a6fa8c-2fde-5e09-92a3-aed3d0d38a60
OperationStatus         : Succeeded

#>

I use this Gist in my blog post on http://blogs.msdn.com/b/pkirchner/archive/2015/01/08/tipp-ressourcen-in-azure-beschriften-und-dokumentieren.aspx.