UML is going to become industry standard in coming years. So it is better to learn it write now. By using UML , you become independent of the progamming language. Everyone all around world will talk one language that is UML. The platform will be common. This will be tremendous boon. It will be great help to Project Managers , Project Leaders & Programmers as the projects can be discussed effectively using UML diagrams , without communication gaps.
Suppose you have mastered UML & you want to explain
JAVA API 's to anyone, you can explain with greatest ease by using class diagrams.
I think some way or other way s/w companies are using UML.
I agree with Grzegorz Klebus saying " Simply visualizing your designs in UML won't make you / your colleagues write better code". But , there are tools like TogetherJ which generates Java code as you go on generating the model with UML. more such tools may come in future.