The opening weekend of Pac 10 play had the Arizona schools in northern California, and the Oregon schools taking on UCLA and Washington (USC and WSU don't field softball teams). ASU swept its three games -- one at Cal, two at Stanford. Arizona, by splitting two with Cal and beating Stanford, ended up with a 2-1 record, whereas Cal and Stanford each had losing records for the weekend.
UCLA also was a perfect 3-0, with two wins over Oregon and one over OSU. Washington had its one scheduled game with UO rained out, and split with OSU.
At the end of the Big 10's first weekend of play, traditional powers Michigan, having taken two games from each of the Indiana schools, IU and Purdue; and Northwestern, with a pair of two-game sweeps over Wisconsin and Minnesota respectively, are tied atop the conference at 4-0.
Only two Big 12 teams still have perfect conference records at this point, Texas A&M (6-0) and Oklahoma (4-0). Baylor is struggling at 1-5.
For further details, see the various official conference and team pages in the links section on the right. The SEC, in particular, provides nice weekend round-up articles, which saves me a lot of work!