Yoshitoshi ABe is the character designer for Serial Experiments Lain, as well as other popular anime, such as Niea_7 and Haibane Renmei. Ueda Yasuyuki, who came up with the original concept for Lain, invited him to come work on the project after seeing his art online. Abe was a senior in art school at the time. A collection of his art for the series was released as Omnipresence in Wired, which features the short manga, The Nightmare of Fabrication.
One of his recent project is a series called Despera, set in 1930s Japan, with a main character named Ain who looks very similar to Lain.
He may be found on many online communities, such as Twitter or YouTube, usually with a screenname of Abfly, or similar.