Here is a free PDF of one of my favorite versions of the Yoga Sutras :
http://www.arlingtoncenter.org/Sanskrit-English.pdf
By Chip Hartranft
"This online addendum is meant to facilitate the process of study and absorption, making it possible to read the lines in English exactly as they flow together in the original text, with selective interjections of commentary, and at the same time to follow alongside with the Sanskrit text. In this way, the reader might come more fully to appreciate the extraordinary richness of Patañjali’s language and the subtlety of his approach.
"Although the book and its related offerings are meant to help the reader follow the path of realization to its end, one must acknowledge that it is as difficult to do so alone from a book today as it was then. It is hoped that this work will clarify both the possibilities and the limitations of the Yoga-Sûtra, indeed, of all words, to bring about wisdom and the end of suffering. It will only have succeeded in this to the extent that it inspires the reader to action, and to stillness.