There is some good info, but also some misleading info in this thread. The most common tuning for soprano, concert and tenor ukes is gCEA. I like this re-entrant tuning for chording. Often players will employ a "low G" tuning which is GCEA, like the top four strings of a guitar, capoed at the fifth fret. If you play a lot of single string melody, this might be a good tuning for you.
Some folks like to tune their ukes, especially sopranos, a full step higher to aDF#B and some instruction books are written for this tuning.
An 1950s entertainer named Arthur Godfrey popularised the baritone ukulele, which is a larger uke, tuned like the top four strings of a guitar DGBE, sometimes called "Chicago tuning".

I notice that this thread was started 12 years ago, right near the beginning of the current Ukulele revival, so much of this information might be old hat to most Mudcatters.