Very simple.  It's in a canister, located on the driver's side of the
engine, back near the firewall.  It's got a black plastic cap on it.  You'll
need a 1-1/8" socket to fit the hex head on the cap.  Unscrew the cap, and
lift it (with filter attached) out.  With a drain pan under the engine, flip
the yellow lever at the bottom of the canister.  This will drain the
canister of fuel.  Spray down the inside with brake cleaner, which will also
drain out.  Close the drain, remove the old filter from the cap, put the new
filter on, remove the old O-ring from the cap, and put the new one (comes
with the new filter) on.  Lubricate the O-ring with a little diesel fuel,
replace the asembly, and tighten the cap just until it bottoms out on the
canister.

Use only Fleetguard fuel filters, available either locally from a
Cummins/Fleetguard dealer, or online at http://www.genosgarage.com.  Don't
pay twice the price for the same filter at the Dodge dealer.

Being a 2005 I would not worry about it. I have a 2000 with 100k miles. I
started using bioD around 90k and had no problems.