How does redirect are used by Google?

Does many different URLs to get to the same page will be seen as SPAM?

[NetRoll]

Let's presume the following site :

www.widgets.com/somedir/somefile?anincredible=param&that=neverends

I would like to know how Google will manage if I define those URLs redirecting to the first one :

www.widgets.com/keyword
keyword.widgets.com

How will Google handle this?

And eventually, would I have to use one of the short URLs within my site to bring this acceptable? This will cause higher use of my server because of the redirections though...

[FreakyIndian]

I'm working with 5 domains which point to a single JSP file, and depending on the domain typed in, the logo changed. Google refuses to index those pages, it seems to be very biased against redirection.

[NetRoll]

Just found this

Don't create multiple pages, subdomains, or domains with substantially duplicate content.

[google.ca...]

So... better not to do.