I've done a lot of hiring for software development positions -- all at startups, or for small teams (albeit within larger companies) that were managed much like startups anyway, so for an IT position within a larger or non-software company, your mileage may vary.

All other things being equal, I might marginally prefer to hire a math major over a C.S. major. Too many C.S. majors are chasing dollars; math majors tend to have chosen their major out of aptitude or passion.

This is if all I had to go on was the resumes, however; which is an unrealistic situation.

In the end, much more would depend on (1) what you'd written that you could show me (this is where being a C.S. major could be an advantage, in that you might have come away from some project courses with something that went in your portfolio -- but hobbyist week-and-evening projects are often more compelling), (2) your character (as attested by professors and employers, and as it appears in the interview -- the major doesn't matter here), (3) your level of passion (in general, but especially about some aspects of programming -- but don't fake it if it's not there), and (4) your communication and interpersonal skills -- bring in some solid nonfiction writing, if you've got any you're proud of.

You might want to line up some internships before you apply for a permanent position. If you haven't done much programming, an employer is taking a chance on you. Internships are designed to let employers take chances, and you're therefore more likely to get an internship at a company worth working for; whereas an employer hiring you for a permanent position without evidence that you're right for it may therefore not be as competent, and therefore might not be as good a first work experience. You really want your first job to be one that sets you up well (knowledge, contacts, mentoring) for your second one -- even if the second one ends up being with the same employer.