I had collected my visa weeks ago.
As I know,the visa normally is valid for 35 days from the date of approval.Therefore I have to use this visa before Oct.1,2008.Once I enter into Singapore,the officers at the entry point will decide the length of stay,normally from 2 weeks to 1 month.
My conclusion is to apply visa of singapore outside China is not a difficult thing.You can call to consular service in advance to know about the necessary documents and bring all together to apply for it,it will be successful.
I hope the info can help some other people.Cheers!