Filb.de has posted the in-game box sprites of all the new Pokémon in Diamond and Pearl. The small images reveal evolutionary connections with Pokémon of previous generations and new lines.
Pokémon from previous generations gaining pre-evolutions: Roselia, Chimecho, Sudowoodo, Mr. Mime, Chansey, Snorlax, Mantine, Porygon.
Pokémon from previous generations gaining evolutions: Roselia, Aipom, Misdreavus, Murkrow, Sneasel, Magneton, Lickitung, Rhydon, Tangela, Electabuzz, Magmar, Togetic, Yanma, Eevee, Gligar, Piloswine, Kirlia, Nosepass, Dusclops.
Eevee and Kirlia have gained split evolutions. Eevee can now evolve into a Grass-type and Ice-type Pokémon by unknown means. Kirlia can evolve into either Gardevoir and the new evolution, which is Psychic/Fighting and 100 percent male. It is assumed that Gardevoir will become exclusively female to match.
Previously revealed Generation IV Pokémon with pre-evolutions and evolutions: Naetle (two evolutions), Hikozaru (two evolutions), Pochama (two evolutions), Mukkuru (two evolutions), Bippa (one evolution), Korobooshi (one evolution), Korinku (two evolutions), Zugaidosu (one evolution), Tatetopusu (one evolution), Minomuchi (one evolution), Buoysel (one evolution), Cherrim (one pre-evolution), Nyarumaa (one evolution), Lucario (one pre-evolution), Dorapion (one pre-evolution), Manaphy (one pre-evolution).
Some sources are reporting a Lapras pre-evolution and/or evolution, but this is incorrect. The Pokémon suspected of being a pre-evolution is unrelated.