At Interson we have sold 1000s of probes for use in EMS.
This podcast from EMS World discusses some of the advantages – Word on the Street: Why Ultrasound Belongs in EMS
Training on how to use ultrasound in EMS is available from a number of sources.
Here is a great book – Essentials of Point-of-Care Ultrasound
Here is the EDE course that uses the above book –
Point of Care ultrasound training comes to you!
I look forward to adding more links as I discover more!