The Freespace 1 port to FS2 is available on
Hard Light Productions (a jewel site for Freespace). The direct link to the port itself is
here.
You do not need to have FS1 to play the port by the way: you merely need FS2 and a speedy connection if you want to download all the music/animations/voices (otherwise, it weights a fairly reasonable 15 mb or so).