Subdomains and app's

[eluser]qICEp[/eluser]
I always loved sites that are well organized and have nice SEO friendly links, CI is MVC based and its it has these SEO friendly URL's but what about multiple applications and subdomains?

Usually CONTROLER is acting like APP, for example FORUM on these website...but i would like to create it as standalone APP and be able to access it either by subdomain

Code:

http://application_name.mysite.com/controller/method/id

OR

Code:

http://mysite.com/application_name/controller/method/id

I have read Multiple Sites subdomains for Single CI system but i dont rely like these method cos it seems to be a bit dirty...

Any advices about these?