EverSpin was spun-off Freescale in June 2008, to handle Freescale's MRAM development, and is now an independent company. EverSpin is the world's first and only MRAM producing company, offering MRAM and STT-MRAM chips.
MRAM related companies
Grandis
Grandis, established in 2002 and headquartered in Silicon Valley, California, develops Spin Torque Transfer based RAM technology (STT-MRAM). STT-RAMTM is a "second generation" magnetic random access memory (MRAM) which solves the writing current scaling problem for conventional MRAM.
Freescale

In July 2006, Freescale became the first company to offer commercial MRAM modules (4 Mbit,25$).
Crocus
Crocus is an early stage startup, headquartered in Grenoble (France) with operations in the Paris area and in Silicon Valley.
NVE corporation
NVE develops and sells devices (Sensors and couplers) using spintronics. NVE is also into MRAM research, and lists Motorola, Cypress and Agilent as licensees.
NVE trades in the NASDAQ (ticker is NVEC). You can follow the latest spintronics news from NVE here.