I'm as new to this as you are (maybe newer!), but I have the exact same setup you do (40D and 430EX I) and just today I received a cheap set of ebay triggers that seem to work fine (in manual mode only, of course, not ETTL). These triggers are both radio and optical, and I tested them quickly in both modes and they appear to work perfectly. "Perfectly" means that the remote flash fires by radio or if the setting is changed, by optical if the 40D's built-in flash fires. If the 40D is set within normal flash sync shutter speed (up to 1/250) the image is well lit with no curtain shadow. The triggers are the Yongnuo CTR-301 series. Good luck, HTH!