Just like when you were a little kid!

Seriously though, beware of large puddles. Sometimes they may hide cracks/holes that can wipe you out and often times deritus collects in them and can occasionally cause flats.

Full fenders are your friend, and if you want to keep your feet dry add a "mudflap" to the bottom of your front fender - which can range from a piece of milk jug to something fancy like a leather flap.

If I have enough speed and am familiar with the puddle I will sometimes just lift my feet and coast through.  This keeps my feet and legs from getting sprayed.  If it's a really big puddle, I'll slow down to prevent spray.  Critninja raises a good point about hazards though...always ensure there are no surprises lurking.

Yes, puddles always seem to be a stumbling block for cyclists on the pathways.  As for dealing with them, it really depends on the pathway itself, your surroundings, and ultimately your own decision making skills.  I realize this probably goes without saying, but if you can quickly sneak across the yellow line or take a short detour into the grass to avoid the puddle completely, go for it (unless there is some obvious impediment on the opposite side of the pathway such as a pedestrian, or something in the grass).  If avoidance techniques are out of the question, what I usually do is slow to about 5km/h (walking speed or slightly above) and gingerly go through it.  Anything faster than that and you cause a mini tsunami that saturates not only anything around you, but also your bike and backside.  Also keep in mind that anything potentially obstructive under the puddle will be invisible, so hopefully that puddle won't be covering the large crack, exposed tree root, or small boulder that will undoubtedly wreak some havoc if you hit it unprepared.  Stay alert and stay dry!