URL Structure / Sub Folders for SEO

[directstores]

We're getting ready to make some changes to our web site which will force us to change our URL structure for each product.  Is there any benefit to having a sub folder in the URL that includes a major keyword for the page?

Current: www.mysite.com/keyword/partnumber.html
New: Current: www.mysite.com/partnumber.html

We have pretty good natural search results and I don't want to screw things up be changing the URLs - would use 301 redirects.

Thanks!

[Hogward]

Yes absolutely, having major keyword in URL is an added advantage to list the page in search engine result. Search engine give more weightage for the keyword in URL.