We are hoping for the last week of April, as well.
We werre there for the official opening of Mission Space, and Philharmagic, and both of them were already running a few weeks before that, so I'm really hoping that Soarin will be the same. We will be home by the 5th (its official opening)
I think I read somewhere it will officially open May 5, as that is the start of the 50th Anniversary for Disneyland. I could be wrong, but for some reason, that specific date stands out in my mind.
"Further to the recent Cast testing, it now appears that barring any problems, Soarin will begin guest soft openings on March 16 2005. The Land pavilion is still under major construction, so entrance will be via a side entry. Remember as with all soft oopenings, the are subject to change, and are not guaranteed."