Many free font sites offer a database of script fonts, such as that offered on the Dafont website at www.dafont.com, where you can find each of the fonts discussed above. No matter which font you use, however, it's worth testing the readability of the text.
Ask one of your elderly relatives to read your invitation to make sure they can make out important information, like the date of the wedding. If they have difficulties, you may want to limit your use of script fonts to accents or the names of the wedding party.
For the do-it-yourselfer, here are some more tips on creating your own wedding invitations:
Also, check out Finding and Using Free Fonts for Windows for links to fonts that can be used for a variety of desktop publishing projects.