My fiance and I currently in escrow, and the replies thus far haven't given you any information that I would've found useful when I was in your shoes. Ideally, you want to put down at least 10% of the house value, so this could be anywhere between $30-$50K that you'll have to spend upfront. This downpayment doesn't include "closing costs" which will add up to about $15K (sometimes these are waived based on incentives). My estimates are based on southern California homes that are up to $500K. So plan on dropping $55K at least right away for your downpayment and closing costs.
First, take your monthly income and subtract any debt obligations you have for the month such as a car payment, student loan, personal loan, average credit card payment. These will all factor into how much of a mortgage payment you can afford per month. This will also give a "back of the envelope" calculation and show you if you'll qualify for a good home loan. Ideally, you want a 30-year fixed rate if you're conservative type. Let's say you make $3,000/month and your average credit card balance is $200/month, you technically have $2,800 for a mortgage payment on paper. Again, you should make adjustments on what you can really afford based on food, gas, electricity, savings and any other expenses.
Second, google "mortgage calculuator" and work backwards to how much of a home loan you can afford. You can do this many different ways, but the easiest way is to just start with a total number say $450K as the amount you're borrowing, and $50K as the downpayment and 4% interest rate if you have excellent credit. That will give you the monthly payment and then you can adjust the above numbers when you compare it to what you can afford in the first step above.
Finally, once you determine everything you find what you can afford, you get a real estate agent and let them know your situation, they should help you out with finding your house, a mortgage broker, any other questions along the way.
Hope that helps a little...
you should decide what kind of home you want (ie single family residence, townhoouse, condo). Once you do that, start looking at homes for sale that meet your criteria