This is definitely something you can do yourself. Dodge has made it pretty easy to accomplish this with a small amount of tools.
Tools Required:Phillips head screw driver;T-30 sized Torx bit (looks like http://en.wikipedia.org/wiki/File:Torx-Bits_T15-T20-T25-T30.jpg
Disassembly:First, remove the 2 screws on the bottom of the door, there's one on the left and one on the right.
Then, remove the screw in the small triangular piece of plastic on the top-front of the door panel. This small piece of plastic looks like it's connected to the window, but it's not. The Infinity brand name may be on this piece, if you've got the Infinity speaker system.
The last of the phillips head screws you need to remove is in the middle of the panel, directly behind the door handle.
Now, grab your Torx bit and we're going to remove the door handle. Pull the door handle up, like you're going to open the door, and you should be able to fix your driver behind the handle and unscrew the bit. The door handle should be completely off now.
Next, pull up on the door panel and you'll feel the hooks securing it to the door release. You'll have to pull all the way up and out. Sometimes it will feel stuck and that's because the door lock fist snugly in its hole.
When the door panel comes loose from the door, you'll have to stick your hand behind the panel and disconnect 2 wires running to your control panel (for windows, locks and mirrors). This is done by just pressing the tab on the connector and pulling down. This should not be extremely difficult to remove.
Now that the door panel is free and clear, remove the 4 screws from the speaker and pull it out. There is another connector running to the speaker you will have to disconnect.
Take your new speaker, connect it where you disconnected the old one and put the screws back in.
Re-connect the window and lock connections coming out of the door to the door panel.
Slip the door lock back through it's hole in the panel.
Press the panel against the door tightly and pull the panel downward, the entire panel should feel secure against the door. If it does NOT feel secure and tight all the way around, then pull the panel back up and try it again.
Once the panel's back on, put the screws back in and re-attach the door handle.
Enjoy the music!