Learning a language is much like learning how to drive.Only when you practice again and again can you improve your skill.My suggestion on learning english,especially on oral English is listed below:
1.Try to speak in English whenever possible.You can join some English club,you can speak English with your freinds who are also learning English.
2.When chat with your freinds or workmate via Email or MSN,try to use English.
3.Read aloud in English.You can read some funny stories,you can read news papers,you can read journals,whatever.Just remember to read aloud.This can make you have courage to speak aloud in English when you have to talk with foreigners.
4.Watch English programs.I here recommend the Freinds.It's a really funny US TV program.
To sum up,just take you time and practice.