This application allows you to read large Text (.txt,.text), Palm Doc (.pdb), Mobipocket (.pdb,.prc,.mobi), Plucker (.pdb), HTML (.htm,.html), and FB2 files quickly and efficiently on the iPhone. This application lacks many of the advanced features of ruBooks or Books.app, but it can quickly load and display large text files that currently cause Books.app or other UI Text View/Web View based apps problems.

Changes:

Adds a first pass at search … it always searches from the current position and the search term will be at the start of the text if it is found.
Click on the Magnifying glass to get the keyboard and search field
click on the text area to make the search/keyboard go away without having to do a search
Type in your text to search fo and select, SEARCH. The last search string is remembered, so you can do multiple searches with a few clicks.
If the string is found, the text window will appear
If the string is not found in the remaining text,a message will appear above.
You can supply guesses as to what you think the other new icon is for 😉

http://code.google.com/p/iphonetextreader/