There are slight differences between buying short sales and foreclosures, the main difference to consider is time. When you find the perfect home your Realtor will prepare a purchase agreement that will be submitted to the seller for either an approval or denial.
In the case of a Foreclosure the seller is the bank. With a short sale the seller is the person on title of the property and when they accept your offer, the offer is then submitted to the bank and they will determine whether the purchase price is acceptable or not, usually determined by what the bank has to have as a final net take away on the sale of the property and typically this process can take 1 month to 6 months or longer depending on the bank. With a foreclosure purchase the buyer with the highest and best offer will usually be granted the opportunity to purchase the property.
After the offer has been accepted escrow is then opened and you can typically close on your new home within 14 to 60 days depending on your financing method.
Great video below provided by The National Association of Realtors: