Links
Following are some helpful links.
EDI Trading Partner links
National Heritage Insurance Company (Medicare Jurisdiction A DME MAC)
California Medicaid (Allied Health) EDI
North Carolina Medicaid EDI
Washington State Medicaid EDI
New York State Medicaid EDI
Utah Health Information Network (UHINT)
Other links
The Washington Publishing Company (X12 code sets, taxonomy codes)
Centers for Medicare and Medicaid Services (CMS)
Because everyone needs a laugh :-)
Massachusetts Medicaid EDI
Adminastar Federal (Medicare Jurisdiction B DME MAC)
Jurisdiction A EDI Enrollment Forms
Jurisdiction B  EDI Enrollment Forms
Jurisdiction C  EDI Enrollment Forms
Jurisdiction D  EDI Enrollment Forms
Cigna Medicare (Medicare Jurisdiction C DME MAC)
Noridian Administrative Services (Medicare Jurisdiction D DME MAC)