The process is called "Re-Flow" soldering.
Firash, without being disrespectful to you, it sounds as though you have a lot of enthusiasm, but have yet to gain the knowledge and experience.
I understand this position is not the easiest to move forward from sometimes, but simply banging out question after question is not the best way to approach it.
Hit google, use the search engines on the forums across the net, read, read and read more.
Then when you have questions, they will be within a context of your knowledge and communication can begin efficiently.
There are cheapo hot air stations, and you can do some qfp and smd with them.
Most of them come with the caveat they may kill you, and have to be checked by experienced person, so I am not posting links.
Someone with the *atten*tion spam would find them anyway... at your own risk.