There are several artists using this name:
1) Ultra-hooky, dramatic vocal harmony-drenched tunes. Echoes of the Beatles, Harry Nilsson, the Beach Boys, and Phil Spector are everywhere. Hal go beyond imitation and use their influences, as a good band should, as guides and not blueprints. Tim Sendra-All Music Guide.
Dublin 3-piece, Hal, formed in 2003 and were signed by Jeff Travis to Rough Trade Records in 2004. Their eponymous debut album was produced by Tears for Fears' Ian Stanley, and released to critical acclaim in 2005, producing two UK and Irish top 40 chart hits.
2) HAL is also an eclectic electronic collective formed in the early 90s by Raheen (Paul Gallagher, RIP 2004), Pádi Stáid, Px (Pascal Derycke) and Savage (Duncan Lomax), who were also active as Black State Choir, North Pacific Drift and Halspirit.
They released their debut album Gorilla Conspiration 1995 on PDCD. Most popular track is Extremis which they recorded together with actress Gillian Anderson in 1997 and which has been remixed by various known artists, such as In the Nursery, The Humble Brothers and Download. In 2004 they released the remix compilation "Extremix".
Now active as HAL And The Big 5 (new album "Umoya" released in 2008).
3) HAL is also a common spelling for the Japanese group HΛL. (The middle letter is a lambda, but its resemblance to a capital "A" makes that substitution common.) Another common approximation is H/\L (using a forward- and backslash to draw the lambda).
4) HAL is also the name of an American 'industrial' band from the early-to-mid-90's. Hailing from Detroit and having only released a couple albums, they were not very well known. Their most notable release from 1996 entitled "Audiophile". It was both an album and a remix album.
5) HAL was also a project by Keris Howard, basically a continuation of Howard's previous band Brighter (on Sarah Records) with a name change. There was one release -- a four-song ep Election Day on Vinyl Japan Records in 1994. Howard shortly dropped the "HAL" name for "Harper Lee." This HAL's tracks are "Election Day", "Clear About This", "I Wish I'd Never Said That" and "Somedays".
6) HAL is also short name for croatian fingerpick guitar player Damir Halili?. HAL released albums "Gemini" (2002), "Ocean" (2003), "Infinity" (2004) and "Trilogy" (2006).
7) HAL is also the name for the company behind such games as the Kirby series and the Mother Series.