Hi Thomas -- Very sorry to hear of your situation. You have a lot of company.
I don't think your mortgage company would care whether you're renting it out (unless you have one of the special downpayment assistance loans that came with a lot of strings attached to it). You should be able to figure this out by looking at the conditions on your note (these papers were given to you when you closed on the condo). Of course you should tell them of your change of address so that you'll get any notices that they send out.
Your condo association, though, may have restrictions on whether you can rent it, how many units (%) in the building that are rental properties, etc. Look over your condo docs for this information.
If you're going to be late in your payments, but feel you can catch them up, I would suggest you immediately contact your mortgage company and tell them your circumstance. They may be willing to work with you to pay the current payment and a bit of a past payment each month (and not put you into the foreclosure track). This really is a must if you're going to be late with any payments. So many folks don't want to face it and try to pretend it isn't happening--this only gets them into more serious trouble and makes it harder to find a solution.
In terms of telling the county taxing authority, I don't think you have to do that either. We pay taxes in arrears here in Florida, so this year's taxes won't be due until November (the earliest date). Again, if you're not making your payments on time, and your payment includes escrows for taxes, you really need to talk with the lender and let them know your plans.
You can try to sell your property, but in most cases nowadays, this means selling short, which isn't the easiest thing to do. You can check out this option with your mortgage company when you call them to work out a solution.
Hope this helps. Good luck.
Louise Warring, e-PRO, CSP, CNS
Certified Short Sale Professional
Coldwell Banker Residential Real Estate