Psychill, also known as psybient or psychedelic ambient, originated as a sub-genre to psytrance.Tag refers to downtempo, sunshine pop, psychedelic pop, psychedelic music starting from the sixties, to some alternative types of chillout and lounge as well as to Psybient, also known as ambient psy, psychedelic ambient, ambient goa, ambient psytrance and more commonly within the Goa/psytrance scene as psychill and psydub, which is a genre of electronic music that combines elements of psychedelic trance, ambient, world music, new age and even ethereal wave. It often has many dub influences and can also sound somewhat like glitch. Psybient pieces are often structured around the concept of creating a “sonic voyage” or “musical journey”. Although similar to psytrance’s emphasis on maintaining non-stop rhythm throughout the night, psybient is far more focused on creating a vast soundscape that can be experienced over the length of an album, focusing less on beatmatching and allowing for a myriad of tempo changes. Some of the most popular and genre leading psybient artists include:

Shpongle
Ephemeral Mists
Entheogenic
Shulman
Ott
Third Ear Audio
Doof
Warp Technique
Yestegan chaY
Younger Brother
G.A.N. 665+1
The Infinity Project
Pitch Black
The Mystery Of The Yeti
Celtic Cross
Androcell
Carbon Based Lifeforms
Sync 24
Solar Fields

Full list available here

The first psychill tracks appeared as the compulsory "chill out" tracks at the end of Goa trance albums and compilations. Psychill originated, like psytrance, in the smallest state in India, Goa. Because of the heat, humidity, and dust in Goa, the birthplace of Goa trance, DJs tended to use cassette tapes or DATs instead of vinyl records. As a result, beatmatching was very hard. As a solution to the dilemma, a production technique developed of having relatively long atmospheric portions in each track, which would allow a DJ to easily mix two tracks of different tempos without having them clash.These short periods that were free of heavy, bass driven beats acted as "chillout" periods for those who were dancing (or "tripping") to relax and regain their energy for the next track. These atmospheric interludes in the Goa trance parties were the roots of the psybient/psychill genre. One of the best places to listen to free psybient music is
www.musicofthegods.com/

biggest web portal with news from psybient, psychill, ambient scene
www.psybient.org