This won't help you get into your truck, but FWIW, I always keep a spare key for my current vehicle in my wallet.
I keep at least two other spares at home - obviously I'm a great believer in spares.
CAA (AAA in the states) or any reputable (or even disreputable) tow truck operator will know how to get into virtually any vehicle, and they usually have the specialized tools (and the practice) to do so efficiently.
Other than that, all I can say is that the good thing is that usually, something like this will only happen once, since next time, you'll probably be prepared (if you've learned your lesson).
Oh, and I'm not prepared to outline how to use the antenna trick either.
'03 Ranger Supercab, Flareside, 4.0 liter V6 SOHC, auto, 4 x 4 w/FX4 Off-Road Package (Level I)