There are multiple artists with this name:

1) Celtic Cross consists of Simon Posford (Hallucinogen, Shpongle, Mystery of The Yeti), Soul Davies (James) and Martin Glover aka Youth.

You can almost taste the Shpongle in this ambient but also exciting project, with trippy sounds and a nice flowing bassline, sometimes along with parts that sound they could be played on banjo. Especially in the song fittingly entitled 'Hicksville'.

The style of music was not psychedelic trance (although their album sometimes considered a psychedelic trance album), but rather psychedelic ambient/dub with ethnic influences. The cover of the Hicksville album was designed by Mark Neal, the same artist who worked on Posford's Twisted and The Lone Deranger, as well as the Shpongle albums.

2) Celtic Cross is also a Czech band playing Irish and Scotish Traditional songs. They released one album "Live" recorded in 2005. As their biggest success we can consider their part on Beltaine 2007, traditional Celtic festival in Czech Republic.
http://www.celticcross.cz