I'm hoping to do it again in mid-June via Avalanche Gulch. Here are some links I use -

Real-time cam of the mountain.

Mt Shasta Avalanche Center

Mt Shasta Climbing Advisory (this one especially helpful)

In addition to the 5th Season, call the USFS Ranger Station. Have always found them most helpful and accurate with their conditions report.

If anyone's interested in an old trip report, here's one I did back in 2006 - http://www.hewhohikes.com/Mt%20Shasta%20Trip%20Report.htm

If anyone knows the availability of running water at Horse Camp please post it here.