IMEI generator advanced is a great tool for generating IMEI numbers for your mobile phones. It comes packed with the ability to generate both phone specific IMEI and random IMEI. Depending on your choice, you can choose to generate IMEI for any phone currently supported, more support will be added in subsequent updates.
IMEI generator advanced also comes with a great tool for verifying the validity of any imei number provided. This checks if the IMEI number is valid and breaks it down into various sub numbers.
Watch out for more phone support.