[support] Search and GET or getting GET param and param through URL

Where is the FM to learn how to deal with GET parameters and parameters to hooks?

I'd like to have a search form whose results are bookmarkable.

So <form action="/d1/search/items" method="get" > <input type="text" name="code" /> <input type="text" name="name" /> </form>

etc...

so that the resulting url would be /d1/search/items?code=111&name=222 or (?) /d1/search/items/?code=111&name=222

Once I've a search/items hook how can I read extra parameters in the drupalish way?

What if I want to pass parameters to a hook through a url?

eg. I've nameset/dosomething and I want to pass a=7 and b=10 in a similar way as nameset/dosomething/a/7/b/10 or nameset/dosomething/7/10

thx