If you already have a house in mind or at least an area then you will be better prepared to know the costs as they are dependant on area for property taxes, HOA fees, and property insurance.
On a monthly basis there is PITI, Principal, Interest, Taxes, Insurance.
Principal - The Amount of the loan
Interest - The cost to borrow the money
Taxes - can be anywhere from 1% of the sales price to 2% of the sales price.
Insurance - Property Insurance
Depending on the type of loan you get these items may be included in your payment. Also there could also be PMI insurance depending on your loan.
You really need to speak to a lender who will explain in detail the costs associated with the property you are thinking of purchasing.
Here's a PITI calculator, http://www.realestateabc.com/calculators/PITI.htm you can experiment with but ultimately speaking to an experienced lender will give you the best information: