There are popular net sheet programs in the market. PalmAgent, CostsFirst, TitleCapture -- What one do you use to simply calculate the buyers monthly and down payment required or the Seller's net out of a transaction after all closing costs.
PalmAgent and CostsFirst are great tools to determine the costs in your market and deliver a good "estimate" of the transaction.
CostsFirst from First American Title is what I am most familiar with use the Desktop and Mobile apps. Easy to register at no cost - http://www.CostsFirst.com.