Assuming you mean Pokemon Sapphire Version, it can be found at GameStop, or on Amazon.com. Probably also at EB Games or Game Crazy, but I haven't looked, so...
Here it is on Amazon:
http://www.amazon.com/Pokemon-Sapphire-Game-Boy-Advance/dp/B000084314/ref=sr_1_1?ie=UTF8&s=videogames&qid=1266872970&sr=8-1
Sapphire is found in many countries around the world including the US, Tanzania, Sri Lanka, Madagascar and Burma.
Missouri River in Lewis and Clark county Montana, this is were the first sapphire was found in 1865.
Sapphire is Found in North Carolina, so it is real
Pal park cannot be found in Sapphire. It is found in Diamond/Pearl after you get the national dex.
In Pokemon Sapphire, Latios can be found in Southern Island.
There are various resources of finding sapphire. The most popular locations in the world that have sapphire are Burma, Sri Lanka and Kashmir.
If you're talking about Professor Oak, he's not in Pokemon Sapphire.
Groudon cannot be found in Sapphire. Hence, it has to be traded from Ruby.
The HM04 Strength can be found in Rusturf Tunnel in Pokemon Sapphire.
Diglet cannot be found in sapphire only if you trade from other version.
Latios and Groudon, although Kyogre and Latias is available in Sapphire only :)
Pikachu is found in the safari zone.