Previously, I want to create the ebook for my Android phone. Then I look for the software to create ebook and a common ebook file format. Then I found that EPUB is a very popular ebook format. The apps such as Moon+ Reader and Aldiko support EPUB format.
So, to create our own ebook, Calibre is a good choice. It can convert my ODT and DOC files to EPUB. Moreover, the HTML file with table of content can also be converted to EPUB.
If you are command-line oriented, then ebook-convert and ebook-viewer will let you convert the format without import them in to Calibre library. It will be more convenient.
Now, I can enjoy my own ebook with my mobile phone. Great!