I don't know about Jita exactly, but it is certainly a good idea to have a trader alt...
Reasons for this are you can set the character up with High Charisma and willpower which most trade skills need, you lower the taxes you pay, increase the number of sell/buy orders and extend the range of your buying powers by having these skills so it's well worth doing.
I would put this trader into a market region (as stated by Thikron) Then you know your getting the best prices for your goods.
It doesn't have to be the Forge, if you wish to be different go to Amarr or Rens those regions have big trade hubs as well.
In all honesty if you have an alt hauler, once he can use an ity V (assuming you've picked Gallente) then do a remap and learn the trade skills on the same account then you don't have to pedal two characters.
EDIT: I see knee has beaten me too some of this info also :)