TheKub did a good job answering the questions. I'll chime in with a bit more info.
1. When you sign up to sell your house, you sign an agreement. For example, I just sold my house with a realtor a couple weeks ago. My agreement was that the reator gets $295 + 6% of the highest price mentioned in the purchase agreement. The realtor had 3 months to sell the house, otherwise he gets nothing. My realtor brought in multiple people to help him (other selling agents, buyer's agents, etc.) What his agreements were with these other people is basically immaterial to the buyer and the seller. He probably paid the other people flat hourly fees for assitance (such as during an open house). I know for a fact that he paid many buyer's realtors with food (he cooks them regular lunches at the house to get buyer's realtors to see the house). Ultimately, since he found the buyers, he probably kept most of that 6% fee (minus his expenses).
Who you hire will affect who your real estate agent can bring in to see your house. Generally, go with an agent who works at a company with lots of sales. This is since there are (possibly illegal) strong tendancies for buyer's realtors to steer buyers towards sellers with seller's realtors that are more favorable to the buyer's realtor.
2. The average price of houses sold in the US in Jan 2009 was $164,800. The average price of houses sold in the US in July 2009 was $178,400. Plain and simple. Prices DID go up on average. But remember, generally higher priced homes sell only in the summer, so it skews prices in the summer (average prices almost always rise in the summer).
Real estate is also a local thing. Businesses close down in your area, people move out, demand drops, and prices fall. Businesses do well in your area, people move in, demand increases, and prices increase. Nationwide averages are nearly meaningless to you personally.
Here are local price trends in almost all areas in the US.
3. $1k isn't usually enough to do anything. It might help with a "price reduced" sign, or it might give it a stigma of a unwanted house. I think generally a price reduction is worthless unless the reduction is at least 2% of the house price (often 3% is needed).
But, there is one major exception. Most people look for houses online. When you look online, you choose a price range (say $250,000 to $274,999). By moving the price $1000, you might put the house into a whole new category of buyers who never looked in your price range. For example, moving a house from $250,000 to $249,000 will allow a lot more people to see it as now it is in the $225,000 to $249,999 range. Alternatively INCREASING your house price may even help. Instead of being the most expensive house people see at $249,000 (when they search the $225,000 to $249,999 range), increasing the price to $250,000 will make it the cheapest house people see (when they search the $250,000 to $275,000 range).
4. Closing costs are paid by the buyers. The trend right now is for buyers to ask the sellers to pay a good chunk of the closing costs. Ultimately that is often a bad idea though. All it does is have the sellers sell the house at a higher price to get the same amount in the end. So the sellers get the same amount, the buyers have a more expensive loan (and pay higher real estate taxes), and the winners are the real estate agents who collected 6% on a higher price.