2D Dynamic Shadow casting

So I looked up some XNA Dynamic Shadow Casting and this is what I found:

I first found this blog
http://forums.create.msdn.com/forums/t/34665.aspx

which based his code off of this blog:
http://www.catalinzima.com/2010/07/my-technique-for-the-shader-based-dynamic-2d-shadows/

but the first blog is trying to optimize the second one.  This person (I don't know if it's a boy or a girl) also went off of this article:
http://www.gamedev.net/page/resources/_/technical/dynamic-2d-soft-shadows-r2032

Just in case we want to get something going for the next sprint here is just some shadow advice:
http://www.virtualrealm.com.au/Blog/tabid/62/EntryId/154/Drawing-2D-Shadows-in-XNA.aspx

One more:
http://forums.create.msdn.com/forums/p/74436/453356.aspx

Oh heres my search:
http://www.google.com/search?aq=f&gcx=w&sourceid=chrome&ie=UTF-8&q=dynamic+shadows#sclient=psy-ab&hl=en&source=hp&q=dynamic+shadows+XNA+2D&pbx=1&oq=dynamic+shadows+XNA+2D&aq=f&aqi=&aql=1&gs_sm=e&gs_upl=2537l3459l0l3698l3l3l0l0l0l0l418l826l4-2l2l0&bav=on.2,or.r_gc.r_pw.r_cp.,cf.osb&fp=a7d5b7030ebfa2c5&biw=2304&bih=1174