I am guessing here, as you have not provided a lot of information, but let me see if I can take a guess.
You are looking for a place to rent, and people are advertising homes that are in foreclosure and telling you that if you take over payments they will rent it to you. If this is correct let me make a few observations.
1. You will have to do more than just take over payments, you will have to remedy the foreclosure.
By this I mean, if they are 3 months behind, you will have to pay the 3 months rent and any penalties before the home mortgage will be current.
2. You must ensure that if you are willing to do this, that you make the payment to the lender yourself or have an attorney assist you. ~ this is because if you pay all the cost to the landlord and do nothing to ensure it is current, then the landlord / homeowner could just walk away with your money and the remedy may never take place.
3. You must make sure the payments are being made to the lender on a monthly basis and that the payments are for the full amount of the mortgage payment and possibly any escrow such as Taxes & Insurance. ~ if you do not do this, then again, the situation could occur again and you will be left with being stuck living in a home that is in foreclosure, or a home that has continual liens being placed upon it that in the future could be subject to foreclosure due to the liens.
4. I strongly suggest you find a GOOD agent and possibly an attorney who knows your tenant rights and has the tenacity to ensure you are not being taken advantage of and that you are protected and educated.
These situation appear to be more hassle and cost than they are worth, but I am speaking sight unseen without all the details. So all I can do is suggest you protect yourself the best you can.
Despite me being in Florida, these should be relevant and are what I would tell my own client here in Orlandao if asked for my professional opinion.