If you plan on driving somewhere this Memorial Day weekend, be prepared to pay even more than just a few days ago. I put diesel in my pickup this afternoon for a Memorial Day trip to the Black Rock Rendezvous and paid $4.45 a gallon. I wasn't fast enough, though; it was $4.39 this morning. I'll bet a tank full it will be considerably higher by the time travelers decide to gas up toward the end of the week. Right now, regular gas in Reno averages around $3.80.

A little planning and knowledge can help you save a few bucks. The About.com Southwest US Travel guide, Elizabeth Mitchell, has produced a great Gasoline Prices in the Southwestern United States (excluding CA) article with gas price information, money-saving travel tips, and more.

If you are going over the hill to California, it's grim. The lucky among us have a car with enough fuel capacity for a round trip. If not, here's what to expect in California metro areas like Sacramento and San Francisco: AAA Daily Fuel Guage Report: CA Metro Averages. With my diesel example, today I would have paid $4.79 in Sacramento and $4.87 in San Francisco. Regular gas in those places is a few cents on either side of the $4 mark.