HP and Exp System
The HP system has been simplified-- just multiply your pokemon's level by 10, and you'll have its HP. From there, simply add 10HP for each level it gains until it hits level 100 with a max of 1000HP.
We recognize this is quite different from the system some of you may be used to, but it helps compensate for the other alterations we've been making, primarily in regards to attacks in Bulbapedia. It also means you'll have to check this page much less regularly, since the system for deciding HP is the same and a simple multiplication.
Exp
In an attempt to help simplify things, wild pokemon and pokemon used by NPC trainers now give out experience equal to their level when defeated.