Does this mean for the use of this ability it has a reach of 5ft or does it still "leap" into the same square????
Dweomer Leap (Su): "When a dweomercat cub is targeted by a spell or within the area of effect of a spell, it can, as a swift action, choose to teleport to a square adjacent to the spell’s caster, effectively appearing mid-leap and aimed toward the caster. This ability takes effect regardless of whether or not the spell overcomes the dweomercat cub’s spell resistance. If it chooses, the dweomercat cub can immediately make a full attack against the spell’s caster as though pouncing. Using this ability does not provoke an attack of opportunity. If there is no safe space adjacent to the caster—or if the dweomercat cub's chooses—the dweomercat cub can forgo using this ability."
It does not grant reach. The abilities was copied from the normal Dweomercat which is medium.
Another thing is that ability is a swift action, so unless people are casting spells on it during it's own turn, it'll need to use a Ready action to be able to use the Leap.
James Jacobs himself has stated that it was supposed to be an immediate action, not a swift. See this thread (wich I remember partly because I was ninja'd AND corrected by JJ).
EDIT: ninja'd again, because I wasted time looking for and verifying the link to the thread. Blasted cats !