You need a negative indent for your paragraphs. This means you set the left margin of the paragraph to the point where you want the second and following lines and set the text-indent to a negative value.
The CSS looks like this:
Code:
.poem{ text-indent: -2em; margin-left: 2em}
This works in ADE epub, but I don't know if it works in epub for iPad or if it translates correctly into mobi.