Please see the most recent updates in the "Where did the .com name go?" thread. Posts number 16 and 17.
Sure, for FSX I used Traffic X (Just Flight) but perhaps You can find some of free programs from Avsim/Flightsim. For FS9 I used one free programm, for FSX only this payware Traffic X.
For FS9, I used FS Traffic Tools; for FSX, I've not yet gotten around to creating custom traffic, but tools I believe TTools also works in FSX - it needs an FSX converter tool. Dedicated FSX AI Traffic programmes include
AI Flight planner
AIFPC (converter from FS9 TTools format to FSX)
