It's an 8 volumes series of Chinese novels written by Yu Wo and has been adpated in a popular manhua.

It is the year 2100 AD. Technological advancements have made possible the existence of virtual reality, and now the long-awaited has arrived – “Second Life”, a virtual reality game with a realism level of 99%. Provoked by her younger twin brother during an argument over the “unfair advantages” that female players have, Feng Lan is determined to beat her brother without using the benefits of her gender by playing a male character… and thus ends up being the first and only transgendered character in the entirety of “Second Life”.

-> the english translation approved by author : http://halfprince.wordpress.com/

My judgement : the manhua is really good and I've not began the novel... but I will do it and put my judgement here ;)