PackageFactory for U3 lets you convert any application or EXE into a U3P Package File, for free! You can then install this U3P file onto any U3-compatible flash drive.
PackageFactory for U3 works best for simple programs and applications with few support files (although you can add as many supporting DLLs and other EXEs as you need).
PackageFactory for U3 is free to use for non-commercial purposes. The free version above has no restrictions and it will append “U3 build by Eure.ca” to the description of the U3P Package file.