I want to know that online register is start andwhen IIM enter examination start and who and syllabus also ...??

Searching on net I found this :

Most top India Business Schools have an admission process similar to that of the IIMs
1. CAT - The Written Test / Entrance Exam
All B-Schools in India have a written aptitude test as the first stage of screening applicants. The six IIMs conduct a Common Admission Test (CAT), usually on the third Sunday of every November. S.P. Jain Mumbai, Management Development Institute (MDI) Gurgaon, NITIE Bombay and many other business schools and MBA colleges base their selection on CAT scores. Other popular written tests in India include the XAT (Xavier Admission Test) conducted by XLRI Jamshedpur conducts and this score is a criterion for admission to XIM Bhubaneswar, BIM Trichy, LIBA Chennai, XIME Bangalore, Goa Institute of Management Goa and score of other business schools. FMS Delhi, IIFT Delhi and the Schools of Management, IIT (Joint Management Entrance Test or JMET) have their own respective tests.

The written test, the first stage of elimination, tests a student's ability to perform under pressure. The areas of testing include basic mathematics taught till Class X, English taught during the first year of graduation and analytical & logical reasoning. The written test is the most difficult step in getting into a top B-School in India. Most of the elimination takes place at this stage.

About 210,000 students took CAT in 2006. Around 1600 students get admission into one of the IIMs each year.

You can download a sample diagnostic CAT test, which is representative of the written tests conducted by the best Business Schools.

2. B School Application Essays and Reference Letters
Application Essays are an integral part of most top B Schools selection process. While only those shortlisted based on their written scores in CAT are expected to write these essays in the case of the IIMs, some other top management institutes in India such as the SP Jain ask you to write many essays at the first stage itself. In the case of SP Jain, your application essays play a crucial role in getting shortlisted for the next round - viz., group interviews. However, in the case of the IIMs, they could form the basis for the interview process. IIM Bangalore, in the recent past, requires those aspirants who have cleared CAT and been shortlisted for the GD-PI to produce three letters of reference. So, if you are planning to apply to these places, meet one of your friends who has applied to these schools in the past and get his applications to get an idea of what is generally asked.

3. Group Discussions / Personal Interviews - GD / PI
Based on the performance in the written test, students are short listed for a Group Discussion and Personal Interview. At the IIMs, anyone who is shortlisted for the GD PI process attends both the group discussion and the personal interview. GD is not an elimination stage at the IIMs. However, other b schools could have the GD as an elimination process.

4. Admission
Admission is usually offered based on the cumulative scores of written test, GD / PIs, and work experience (in some cases). Admission notification from top B Schools start from the second week of March and continue till the end of April. Many of the management institutes also have a waitlist of candidates which gets updated based on the number of students in the first list who accept offers made to them.