Obtaining the iTunes store link to an app
In the AppleVis help section, there's a topic which describes how to obtain a link to an app in the iTunes store. I have a more simple procedure which will also help you search for interesting apps.
In to google, type the information you are seeking, for example "SIP client iPhone" or "app compatible voiceover" or "text adventure iPhone" Don't include the quotes unless you want to match an exact phrase. After that, type iTunes, and submit your search. You can then copy the link from your address bar, after you've located the appropriate page through google. By including the word iTunes in your search, you limit its scope so that links to the app store entries should be near the top of the list.
This works well for finding books as well, by typing say "John Grisham" itunes. If you forget to include the word iTunes in your search, you end up often with thousands of irrelevant hits.
Try it too for university courses, podcasts and music. Helps you quickly locate entries in the iTunes store outside of iTunes itself.