Can anyone explain to me how can UML be used in the design phase?can u give me some examples of it... thanx

UML can save you time while designing, and even at times, developing a system. Tools like rational rose or visio can create your classes striaght into your code. I've used visio myself, and it's ability to design the system before begining it gives you a good overlook at what you're programming. In the UML, you create data types & classes with their attributes, constraints, etc. You can also dosument it's psudo code or breif description of what it will do. You also create the operations and return types. When the design is done, you can visualise and project plan, giving you a better idea of what needs to be done first, how long will it take, etc. You can then send your UML to .Net in VB.Net or C#. The classes are generated automatically and you save time, your datatypes and operations are created, psudo code or descriptions are commented. Since you took the time to plan the software and the project, you will have the advantage of assigning what needs to be done.
What do you currently program in and do you have any UML tools???

That's a pretty loaded question, about which libraries full of books have been written.

If you're really interested, throw some money into it and get yourself some professional software analysis and design training.

I took Sun's OO-226 course which was great, and at just over €2000 for a week very nicely priced too.
That will teach you a lot more (and prevent you from picking up a lot of bad habbits) than reading some books and websites with no guidance.

thanx for the reply... actually im nt doing any coding in my unit here in my university for my Software Engineering unit....we are most asked to do documentation like SPMP, SDD, SQA...etc..

the worst education then.
Without knowing how to write code (and thus what works and what doesn't in real life rather than in theory) you'll never create a design that's both theoretically good and can be implemented to an efficient working solution.

Keep in mind, theory and actuality don't mix. You can't create a UML project without knowing what needs to be coded. UML is a Software Architect level, to by that point, that "Architect" was once a Jr. Programmer, Programmer and then Sr. Programmer.
But I understand in school, you must be educated, at least to understand the "basic" theory of things.

You will find some interesting articles on UML either on DMOZ:
http://dmoz.org/Computers/Programmin...uage/Articles/
or in the Methods & Tools newsletter
http://www.methodsandtools.com/