Newhalem 

To Reach the wall:

Park on the South side of Hwy20, at the East end of "town".
Walk along hwy 20 for ~150yrds to a trail on the left, which leads to the wall in about 30 seconds.

Thanks to the years of effort of the Access Fund, the Washington Climbers Coalition and the great National Park Service staff, Newhalem is once again open for new routes!!
The above parties in conjunction with the Vertical World climbing team, the Wilderness Society and the Washington Trails Association just built a new trail to a new mega cliff just down the road. Walk down and check it out and bring your new-routing mojo! There is a decade's worth of potential in this gorge and years of new routes on the new cliff alone!

Also, the late, great badass and all-around great friend Ryan Triplett put up a bunch of new-school hard classics at the main Newhalem cliff ("Newhalem West"). Check 'em out! I'll try to post route info...

FYI there is an online guide (incomplete but a good place to start) here:
www.misha.org/Climbing/Newhalem/index.html

Wow. What a cool interactive topo idea.

What is the season here? Looks like it seeps in spring? Which way do the cliffs face and when does the sun hit them?

Someone else might know better, but I believe Ryan's Wall is south or southeast facing while the other larger wall is south to southwest facing. I think one could potentially climb here year round in the right conditions. Ryan's Wall seems to both dry quickly after and stay dry during most rainstorms. Most of it is in the shade in early afternoon as well.