You can choose certain veteran ships at the shipyards, one per character. I think the defiant, galaxy and intrepid retrofits for feds and the Kar Fi and a BoP for the KDF. You can see which ones as they'll have a V token for the cost were other ships have a zen cost.
And be aware that this is a one time purchase, not a character unlock. If you should delete the ship, the only way to replace it is from the Z-store... Also, ships purchased with the VA Token do not count for Fleet Ship Purchase discounts