I have a 98 also...when I got my truck the driver's side headlight (original) was aimed correctly...passenger's side was aimed straight down at the ground like 10 feet in front of the truck, lol. There are 3 adjustment screws...the one I used needed a 5/32 wrench. Here's a picture of it...
It's a real easy fix...I just used the screw shown above (the top screw). There are 2 more; one about halfway down on the other side (seems to be for left/right adjustment), and the other all the way down on the same side as the one pictured (which is broken on the headlight I adjusted and might not be necessary). Obviously you should fix this ASAP since blinding other people on the road can result in bad things...
Edit: Answer to question #1 from http://wiki.answers.com/Q/Where_is_t...98_Ford_Ranger
The 1999 Ranger 2.5L 4 cylinder PCV valve is located on the driver's side of the engine, approximately between the #1 and #2 spark plugs and under the intake manifold runners. It's on top of a small cannister called the "oil separator." It's difficult to see, especially if it's dirty, so you will probably need a flashlight. To remove it, pull it straight up, out of its rubber grommet. I use a set of long pointed pliers to grasp the rubber hose attached to the top of it and pull it up that way.
I'm gonna go see if I can find mine, lol now you have me wondering...
98 Ranger XL 2wd 2.5L 5spd 3.45 gears
15x7 Pacer black steel wheels, 225/70r15 Cooper Discoverer ATR tires, LED front side marker lights & license plate lights, red LED dome light
GoLight #5149-M (work/off road use only).
Suspension lift, 31 or 32" tires, 4.something gears