The oil companies are not raising prices. The price of oil is in fact mostly affected by supply and demand, with about 20% of the price due to speculation.
Determinants of price of oil:
1) Supply and Demand - Demand is still going to rise because of the developing countries needing it to sustain their growing economy (China and India for example). Also, demand is always higher in the summer months because Americans are driving more. (part of the reason why we saw a 4-5 cent jump around 4th of July).
2) Geopolitical tensions - Standoff with Iran, oilfields buring in Nigeria, problems between the US and Venezuela, and the latest one being the Middle East conflict. These all LEAD investors to believing supply could be disrupted (part of the 20% speculation) so it bumps up the price of oil. Now if supply is ACTUALLY disrupted, say hello to 90 or 100 dollar barrells of oil and about $4-5 at the pump for gasoline.
3) Natural disasters such as Hurricanes. Remember during Katrina when gasoline here in the Northeast (and elsewhere) jumped about 0.75 in 2 days? Supply was greatly disrupted because the platforms were damaged and the pipelines couldn't bring oil from the Gulf to the NE.
4) Gas "boutiques" - There are different regulations many times for different states about what can actually go into the gasoline that is burned in cars. So for example, CA has some of the toughest laws regarding pollution, which is one of the reasons why gasoline is more expensive there. There has to be things added and taken out of it so it can burn more cleanly. Now for example, if CA experiences a gas shortage, oil companies can't then divert gasoline from AZ and send it to CA to alleviate the supply shortage because there are different regulations. These create so called "gas boutiques" or "gas islands." Also, the gov't required the additive MBTE (I believe that's the name) to be phased out of gasoline to replaced with ethanol I believe. The time wasn't long enough apparently and it caused some isolated supply issues, mainly in the Northeast again. This happened earlier in the year because I remember a station near my college had actually run out of gas.
5) Taxes - The federal government has a tax on gasoline as well as state governments. I know NJ's gas tax goes to the funding of the transportation and highway bills. I believe the federal tax is 18.4 cents and here's a link for state taxes:
http://www.energy.ca.gov/gasoline/statistics/gas_taxes_by_state_2002.html
In reality, the oil companies don't control the price of oil or gasoline. They make about 10 cents off that $3 dollars you pay.
And I don't have sources (too many to quote)...I did a paper last semester in college about this very subject.