To get Hitman 2 to happily run in widescreen, you must edit the 'hitman2.ini' file in the hitman 2 directory.
1) Open 'hitman2.ini' (generated after the first run of the game, so if a fresh install, run the game first, the exit and open .ini file)
2) Scroll down to 'resolution', and change it from 1024x768 (or whatever) to your desired widescreen res. (eg: 1680x1050).
3) Change the line 'window 0' to 'window 1', if you can't find it, just create one under the line 'resolution'.
Save and exit. Run Hitman 2.