i want to run this link.How will i code??

[eluser]minhbu[/eluser]
i have link http://mydomain.com/a2324 and http://mydomain.com/news
i want when i use http://mydomain.com/a2324 is server will get param a2324 and use it query in db and return infomation in db.
And if i use http://mydomain.com/news is it will run controller news.

How will i do it ??
Thanks