You're welcome!
Gutenberg files are plain ASCII or HTML and cannot be read directly by eReader. You have to convert them. The good news is that there is a free utility, Dropbook, to do that. The bad news is that if you just run Dropbook on an ASCII file, the formatting on the screen in eReader will be hideous (line breaks in the middle of a line). I'm quite an eReader fan, so I've learned to use its formatting language, PML, and I just go ahead and do the formatting and conversion whenever I want a Gutenberg text. You may not want to go to that extreme.
The only readers I use are eReader (for books that I care about enough to format) and Plucker (for web pages, articles, etc.) If I just wanted to grab something from Gutenberg and read it without fiddling with it, I'd use Plucker and live with the page issue.
There may be other choices that will do what you want, but I don't know of them. That doesn't mean they're not out there. I've never done a detailed investigation.
By the way, you'll find plenty of eReader books for free at
www.memoware.com.