Surf west of Cherrygrove, use rock climb and headbutt the trees. Catch it.
Taillow isn't in Leaf Green, just emerald Sapphire and ruby
breed a swellow and ditto
I know Taillow evolves to Swellow but after that Swellow won't be able to evolve.Answer Swellow is one of the few Pokemon who only has one evoltion. (from Taillow to Swellow)
no you can trade soulsilver pokemon to black
Surf west of Cherrygrove, use rock climb and headbutt the trees. Catch it.
somewhere
Level 23. 
Taillow evolves at level 22.
You can't catch a Taillow in Pokemon Platinum, but you could catch the later evolution (Swellow) using Poke Radar on Route 213, and then breed it to get a Taillow.
The Pokemon taillow is a Flying Type
Taillow is #276 in the national pokedex, and it is a Normal-Flying type Pokemon.
Taillow isn't in Leaf Green, just emerald Sapphire and ruby
swellow
you need to transfer a taillow from either ruby, Sapphire or emerald on a Nintendo ds lite.
i think at level 32
it was taillow