Without seeing the ports of the car and the plug of your charger, it would be difficult to diagnose with any certainty. I do have a suggestion however. Your note suggests that other devices do not cause the fuse to blow when they are used - it is only the charger for the phone. Since the charger works in other cars, it is probably not an overload condition due to a defective charger, but more likely a mismatched set of contacts between the plug and power port in your car when the two are mated. Some cars have slightly different sized power ports that can be either too tight or too loose for some plugs. Too tight ports could be causing parts internal to the charger's plug or car's power port to short together and blow the fuse.
We can get around this be using a different plug. The easiest way is to find a cord set that will plug into your car's power port and provides a simple extension for 1, 2 or 3 outlets. These can be found in auto parts stores and the automotive departments of stores like K-Mart, Sears, etc. Some examples look like these:
Insert the plug into the power port - and check that the fuse does not blow by checking the fuse - not by plugging something into the the outlet on the cord. If the fuse remains good, then it is safe to assume that the problem with your charger and the car's power port has been eliminated, and the car's power is available at each of the outlets of the new cord.
Try plugging the charger into the outlet of the new cord. If all is well, the charger should be working as expected. What we have done is removed the charger / car power port combination from the equation, by providing a different combination to do the same thing - but without the same physical connection that causes the fuse to blow.
You could achieve the same results by changing the charger plug under the right conditions - but many chargers now a days have circuitry inside them that change the car's 12 volts to something different. If you can find the voltage out of the charger and are able to match it with another - it must be the same voltage, polarity, current and phone power connector of course - it should work, too. You must be absolutely sure of the power requirements and your rewiring - if not, stick with the addition of a cord described above.
I hope this helps & good luck!