Melrose Labs SMSC Simulator - SMPP SMSC simulator to test SMS messaging applications.
Twilio - Brings voice and messaging to your web and mobile applications.
HotTelecom - Our company offers virtual phone numbers, toll-free numbers, PBX, SMS numbers and numbers for a registration more than 100 countries. Buy Now!
Nexmo - Nexmo is a simple two way SMS API with global reach and wholesale rates
SMSAPI - SMSAPI.com is browser platform for bulk SMS and other SMS marketing solutions.
BulkSMS - SMS messaging service provider offering two-way SMS communication services.