Worrying about a credit check for an apartment?

I'm getting ready to move to chicago and I'm worried about my credit check. I've had a lot of old problems from when I was a dumb kid and a recent problem with ID theft that I couldn't get cleared up (World Financial Network is notorious for screwing people), but in the credit card that I actually opened myself I have been paying at least a little more than the minimum payment on time each month. I'll also be living with my girlfriend, who I'm pretty sure has spotless credit (I don't think she even has a credit card.) Will her good credit offset mine? Will landlords listen to explanations of bad marks on credit reports? Am I destined to be homeless?

You are not destined to be homeless. This situation all depends on the level of competition from other applicants. If someone with a bunch of cash and spotless credit comes along then you would lose out anyway. You need to keep applying for places until one comes along that will work for you and the landlord.