I went to the Microsoft web site download page for development (maybe there is a seperate page for design) and I could not find a place to download Expression Blend. Does this mean it is being phased out? Is Visual Studio 2010 somehow replacing Expression Blend?
What if I needed to use an earlier version of Experssion Blend because a customer's hand held devie is customized for it? How would I get it?
It's not being phased out. Expression 4 has been released a few weeks ago: http://www.microsoft.com/expression/
Considering using an earlier version, I'm not sure if you can buy it anymore (it has never been free) on Microsoft website (contact them, they'll know more about it) but you can try not to use new features if you're developing for Silverlight and targeting an older version, for example.
Just out of curiosity, how would the handheld device be customized for a particular version of Blend?
Blend 4 supports projects that target WPF 3.5 and 4, and Silverlight 3.0 and 4.0. In other words, if you could use Blend 3, you should be able to use Blend 4.
I am not aware of any way to download older versions of Blend or Expression Studio. It is definitely not being phased out. And as 0xA3 mentioned, it is not free. I have a post about Expression availability and pricing that may be helpful.
The unfortunate news is that you need Expression Studio Premium to get Blend and Ultimate to get SketchFlow, and it's not cheap. The good news is that there a lot of products that will qualify you for Upgrade price. The great news is that if you have Expression Studio 3, then Studio 4 is a free upgrade, but whether or not Blend is included will depend on what version you had previously.