the sight picture is about worthless IMO. i "point and shoot" mine. its faster to draw and be on target this way if it came down to having to use it and with practice can be fairly accurate in the distances for self defense. this does not mean ignore traditional shooting, just practice both ways.
You can use sight paint that glows, bright nail polish like teenage girls wear, or glue on a set of P-11 sights like Gramps300 did. http://www.ktog.org/cgi-bin/yabb2/YaBB.pl?num=1256313149. I use yellow glowing sight paint from Cabela's on the rear and orange nail polish my daughter gave me on the front. I've found the POI is the same as POA with my P3AT. But in a low light shooting situation this set up is pretty worthless. If forced to defend in low light point as best you can before pulling the trigger.
You could also drill dimples or notches where the sights are and fill them with glow in the dark sight paint. People have reported mixing glow in the dark powder with 2-ton 15 minute epoxy working very well.
This is a great little gun, but lets face it, the sights are abysmal.
I tried painting the front and rear different fancy high vis colors and it doesn't work well for me. I do better with the front sight painted white and the rear left black. I think in most cases the amount of time it would take to try to acquire and line up a P3AT's sights would be enough to let a perp skewer or ventilate you. Like others have said, practice point and shoot, that's probably what you'll revert to in a crisis situation at the ranges where this gun would be effective anyway.
The more you practice with this little gun the easier it is to use the sights quickly and accurately during daylight hours. One of the things Ruger did when they stole KT's design was they made the sights a little larger but really no more usable than the original. In fact when I carry both to the range, I really can't tell a difference between the two in terms of sight picture. At night or in dark conditions, the best you can do is point the gun. That's why its necessary to practice point shooting as well. Practice both and you can't go wrong.
My Krazy glued on modified P11 sights left scene at about 150 rounds this afternoon. I started relying on the CT laser after that, and after one quarter turn adjustment, and shaky hands (I'm old}, seven of seven in a five inch square box at about 21 feet. With all the "stuff" I've bought for guns recently, I have a new supply of targets since the Kitty Liter boxes were all used.