SAP

SAP is the world's largest selling Enterprise Resources Planning (ERP) software system. For implementation of SAP you require ABAB developers and functional consultants. If you want to make career in technical then you may learn ABAB and do certifications. It is a good career choice for in case you want to be a functional specialist, you can do one of more functional module certification. SAP professionals are paid above normal developers and Business Analysts. With SAP certifications you can join IT companies or IT department of business enterprises. There is a general shortage of good SAP professionals in India and you can make a good career as SAP professional with experience and gaining expertise. You advised to do SAP certifications from only SAP authorized training partner such as Siemens etc.

To "learn SAP" is a massive task. You are smart to set your sights on ABAP, but please remember that there are two versions of the SAP system:
1. FULL ABAP Stack
2. DUAL ABAP/JAVA Stack
The full ABAP stack systems represent largely the versions prior to ECC 6.0. There are many companies running these systems worldwide, but your skills may become outdated more quickly.
The dual ABAP/JAVA Stack represents the new(er) wave of SAP products which include XI/PI, Portal and Solution Manager. Skills that deal with these products will be in demand for a longer time.
Regarding schooling from home, the books regarding SAP/ABAP/JAVA/BASIS are uniformly poor in content and structure. The authors seem to believe that they are being graded by the weight of the tome as opposed to its general usefulness.
Some of the books by SAP Press are very good and generally short (around 100 pages). The best way to learn is to get one of these books and find an IDES system that you can pay to access (around $100/mo) so you can train yourself.
There is also a program called SAP Tutor that you can consider.