Converting from gasoline to lp gas

Has anyone converted their truck over to lp gas as a fuel alternative? What is entailed in this type of conversion? Is it worth it. I heard that the gas mileage is the same but the cost for lp gas is about half of regular gasoline. Also heard that you can go twice as long between oil changes. Feedback appreciated.
Steve
::feedback:

LP has about 20% less BTU's per gallon, so you would expect to get 20% less mpg. Current prices in my area are $2.40 for gas and $1.99 for propane.
$2.40 minus 20% is $1.92, so per BTU gas is marginally cheaper. Another issue with propane is that it's octane rating is 110. If you don't have 11:1 compression and a modified spark curve, you will waste the BTU's in the propane, lowering your mileage further. You can also expect less power from propane as compared with gas even with engine mods.
On the good side, your engine oil will stay much cleaner and your tailpipe emissions will also be cleaner if you do your engine mods properly.

I know the NYC Sanitation supervisors were driving hybrid gas/ LNG (propane) cars and they hated it b/c of lack of power and couldn't wait to "turn on the real gas". Other negative is refilling, you'd need to find a supplier willing to refuel your P/U.