I just wanted to add to that and mention that the new iGoogle layout and features can be seen by anyone via the iGoogle sandbox and is available to developers who request to be included.
To use the sandbox and see the new layout, go here.
A write up I did on the new iGoogle features in April is here
The official Google announcement of the sandbox was here.
The iGoogle API is here.
The official iGoogle developer blog is here.
The video that accompanied the announcement…
One big change that developers should know about is that the allowable width of iGoogle gadgets is smaller in the new layout (where it was 300 pixels, it is now 260 pixels).
I highly recommend anyone developing Google gadgets to apply for the sandbox and check their gadgets in the new layout.