How to easily input special characters? (encoded in UTF-8)

[Hongzheng Wang <wanghz02@mails.tsinghua.edu.cn>]

Hi,
  The special characters I mean are like 【,∫.
  Now I have to use openoffice to input them, but, you know, the 
opening process of openoffice is so slow. Is there another easier method 
to input them?
  Thank you very much.

--
Hongzheng Wang