Some sort of URL rewriting ...

Question

Hi all ,

   I am workin on a website say www.MyWebsite.com which is similar to a b2b portal . Now here we ve a
number of companies and to each company we are providing a homepage which
will be a dynamic page for all the comapnies.

Now this homepage will be loaded according to the company id passed through querystring
or by some other means.

Now what i want is that i don'nt want to show the querystring value in the url

plus I want to let the company access this page by there company name ...

for example ...

    for infosys : the url shoud be www.MyWebsite.com/infosys
    for abc     : www.MyWebsite.com/abc

something like this in http://www.seekandsource.com :  http://snsvo9.seekandsource.com/kebabish/

i think i ve to do URL rewriting .. bt i m nt getting hw to do ...

Can anyone help me ....

tnx & Regards
s_raj0205