PokemonSoulSilver is pretty much just a rerelease of Pokemon Silver. Pokemon Silver was part of the second series of Pokemon games. Silver was a Game Boy Color game and the first to add real time to the Pokemon series. The adventure in SoulSilver is very much the same as in Silver, but you can now play the adventure on the Nintendo DS series of game systems (Original DS, DS Lite, DSi, and DSi XL).
The biggest difference between SoulSilver and Silver is that SoulSilver introduces a whole new way of training your Pokemon using the Poke Walker. The Poke Walker is a pedometer/virtual pet accessory that comes with SoulSilver. You can load one Pokemon from your storage on to the Poke Walker and then train it as you walk and earn watts to unlock more paths to stroll them along.
The Poke Walker is an interesting new feature to the Pokemon games. It encourages players to take breaks and be active by walking around to train pets up easier. Also, you can use the watts to find items or battle on the Poke Walker. It kind of makes leveling up really easy, as it does not take much activity to get the Pokemon to gain a level when you sync it back up with the cartridge. To some extent this ruins part of the challenge to Pokemon, but at the same time it gives a fun alternative to endless grass fighting that can often be a slow aspect of getting ready to beat a gym leader.
Other than the Poke Walker there really is not much difference between SoulSilver and the old Silver. This makes it not much of a new adventure, but at the same time it is an enjoyable nostalgic adventure through the Johto and Kanto regions. The fact that the adventure is familiar might be a disadvantage and a valid reason to buy the game if you still have Silver and a system to play it on. However, the touch screen play does still make game play a little easier with you not having to press buttons to get to options like saving.
Overall SoulSilver is worth getting for most that love the Pokemon games, especially if you loved Silver and want to play it on the DS. The Poke Walker is the main thing that makes it worth getting for those that get tired of the repetitive battling just for leveling up to continue the plot aspect of Pokemon. The game still has some major flaws, though, that make it not worth it for everyone, such as the graphics have not really been improved and the adventure does not really have anything new. You can use pokemon generator to learn about all the pokemons that are there in Pokemon Soul silver. This is a really easy to use tool that can help you in increasing your pokemon knowledge as well.