Most adult level programs of recent vintage (InDesign, TeX. Scribus) will produce pdf files directly. The usual call for a ps to pdf program comes from those using word processors for layout. The latest version of MSWord has a pdf creation function of unproven quality. But there are two free approaches: 1. The GhostScript suite has a utility script called pd2pdf which does waht it name implies. 2. Open Office Writer will import an MSWord doc file and export a pdf file.
When these latter courses are used a check viewing in Acrobat Reader is essential. Fonts and illos must be embedded in the pdf file.