I believe I read somewhere that those fonts aren't available in other apps due to licensing restrictions (they could only include them in the app if they weren't available systemwide).
If you want to take text images you've created IN Comic Life and use in iWeb or any other app, check this page.
http://web.mac.com/makentosh/iWeb/tipsfromtheiceberg/Blog/22FE7668-9F35-4991-A3A 9-240E2C06683D.html
To get at the actual fonts and make them selectable in your font listings in iWeb and other apps, context-click (right-click, control-click or, on a properly configured MacBook, two-finger click) on the ComicLife app, and choose "Show Package Contents"
Then double click on "Contents",
double click on "Resources"
then double click on "Fonts".
There you will find all the fonts included in Comic Life. You can install them like you do any other font, double click, then click "Install Font".
I DON'T know if having these fonts duplicated in this way will cause problems. Since I have more design ability with Comic Life, I just do all the effects there, and export them out to drop into iWeb. You can check out several pages of my blog where I've used Comic Life and Comic Life Deluxe.