UPDATE : all three invites available to me have been used.
As George reminded me in the comments for the last blog post about Photoshop Express, there is also Aviary – not developed by Adobe – but released as an alternative to Photoshop for sure.
Aviary is a suite of web-based applications (RIAs) for people who create. From image editing to typography to music to 3D to video, we have a tool for artists of all genres.
The module meant to be the replacement for Photoshop is called Phoenix – the Image Editor.
I love their branding – the colors – all the birds.
All details of each tool are available on the Aviary Tools page.
They also have an interesting blog that updates with what users of Aviary have been upto – sometimes with source files and videos of projects.