Clay,
April can be one of the best times to be in the valley. Not too crowded, most of the desirable climbing gets good sun, and you can get a campsite. They've received a lot of snow at higher elevations [on the rim], so be careful climbing at the base of El Cap. Big chunks of ice come off during the day from the top. Much of it breaks up or even melts before hitting the base, but you'll get 'killer' chunks once in a while. Nonetheless, you'll see plenty of folks on wall routes. Church Bowl, Reeds, and the Cookie are good places to climb that time of year. If you want to climb El Cap base routes, try Moby Dick. The Muir Wall/Magic Mushroom arch above protects this area to some extent. Also try Pine Line [one pitch 5.7] as it sits right at the toe of the buttress below the Nose route and misses all of the falling stuff. As for hiking, you'll encounter snow as you hike toward the rim [i.e. Muir Trail].
Current Weather:
http://www.wrh.noaa.gov/total_forecast/printable_forecast.php?wfo=hnx&zone=caz096&county=cac043http://www.wunderground.com/US/CA/Yosemite_National_Park.htmlTry
http://www.supertopo.com forum for better information on Yosemite.
Have fun!