Please suggest me some plugins in WordPress networking

[Viruthagiri]

Hey guys i'm creating a site network using WordPress. Lets say my site name is blahblah.com and lets say i have 10 subdomains like site1.blahblah.com,site2.blahblah.com

Now i want something like this. There will be no articles in my main domain. But i want list all subdomain's articles in my main domain. When they click read more button users have to redirected to original article.

I also want multisite access facility with single registration. That is if a user signed up in my main domain, then he should able to access all my sub domain using the same login credentials. Some says use the same database for all domains. But i dont think thats a good idea. Is there any premium or free plugin available for this feature?.
Thanks

[Zero13]

Check out there. http://www.wordpress.org/plugins

[Viruthagiri]

Check out there. http://www.wordpress.org/plugins

Are you kidding me? If i know the plugin name why would i post my question here?

[Viruthagiri]

By the way, i found the answers. Let me post the answer here. Maybe this will be helpful for others users who have the same question.

But i want list all subdomain's articles in my main domain. When they click read more button users have to redirected to original article.

get this plugin.
http://wordpress.org/extend/plugins/wordpress-mu-sitewide-tags/
it does exactly that.

That is if a user signed up in my main domain, then he should able to access all my sub domain using the same login credentials.

this is built in to multisite. you do not need a plugin for it.

Some says use the same database for all domains. But i dont think thats a good idea.

this is how multisite works your whole network is in one database already.