We are wondering what the difference is between CMMI and ISO Certification is. We are ISO certified. Are there different levels of CMMI certificates? Any information you can send us would be very helpful.
If I had a nickel for every . . . . . well, I'd still be poor!
That's a great question though. A lot of organization's have been certified for ISO (9001/9001, 15504, etc) and wish to leverage that success towards the achievement of a level of CMMI.
Remember that ISO is an "audit standard" and that the CMMI is a "process model," so conceptually they're quite a bit different. Think of the CMMI as a large set of related "best practices" gathered from many product engineering and software development organizations. ISO can be very helpful, especially for marketing, HR, and quality, but it is not specifically focused on engineering and project management as is the CMMI. So the depth of CMMI in these areas is far greater.
You've obviously done some homework because you've identified one of the differences already. There are five levels of CMMI "maturity" with the vast majority of companies striving to achieve maturity Level Two or Three. ISO does not have this concept. Also, ISO is a "certification" and CMMI, although it looks and feels like one, is something you "achieve." The difference ends up being minor though (at least from your perspective) but it is a distinction.
ISO also doesn't focus with such depth and breadth on the various process areas (there are 22 process areas in the CMMI) and the appraisal process for CMMI (called SCAMPI) is quite a bit more rigorous. I'm not an ISO auditor, but my colleagues have told me that, while there is some overlap, the process of adopting CMMI is quite a bit more rigorous, as is the appraisal method (SCAMPI).
Your best bet is to get some education on CMMI through an authorized "Introduction to CMMI" training class, and to engage a Certified SCAMPI Lead Appraiser to discuss your particular goals and objectives as they relate to CMMI. If you email firstname.lastname@example.org you'll be able to start the process of learning more about it.
Best of luck to you!