check the below links lot of info and examples r there
http://www.sapgenie.com/abap/OO/index.htm
http://www.geocities.com/victorav15/sapr3/abap_ood.html
http://www.brabandt.de/html/abap_oo.html
Check this cool weblog:
https://www.sdn.sap.com/sdn/weblogs.sdn?blog=/pub/wlg/1013
https://www.sdn.sap.com/irj/sdn/weblogs?blog=/pub/wlg/1013
http://help.sap.com/saphelp_nw04/helpdata/en/c3/225b6254f411d194a60000e8353423/frameset.htm
http://www.sapgenie.com/abap/OO/
http://www.sapgenie.com/abap/OO/index.htm
http://help.sap.com/saphelp_nw04/helpdata/en/c3/225b5654f411d194a60000e8353423/content.htm
http://www.esnips.com/doc/375fff1b-5a62-444d-8ec1-55508c308b17/prefinalppt.ppt
http://www.esnips.com/doc/2c76dc57-e74a-4539-a20e-29383317e804/OO-abap.pdf
http://www.esnips.com/doc/5c65b0dd-eddf-4512-8e32-ecd26735f0f2/prefinalppt.ppt
http://www.allsaplinks.com/
http://www.sap-img.com/
http://www.sapgenie.com/
http://help.sap.com
http://www.sapgenie.com/abap/OO/
http://www.sapgenie.com/abap/OO/index.htm
http://www.sapgenie.com/abap/controls/index.htm
http://www.esnips.com/doc/2c76dc57-e74a-4539-a20e-29383317e804/OO-abap.pdf
http://www.esnips.com/doc/0ef39d4b-586a-4637-abbb-e4f69d2d9307/SAP-CONTROLS-WORKSHOP.pdf
http://www.sapgenie.com/abap/OO/index.htm
http://help.sap.com/saphelp_erp2005/helpdata/en/ce/b518b6513611d194a50000e8353423/frameset.htm
http://www.sapgenie.com/abap/OO/
these links
http://help.sap.com/saphelp_47x200/helpdata/en/ce/b518b6513611d194a50000e8353423/content.htm
For funtion module to class
http://help.sap.com/saphelp_47x200/helpdata/en/c3/225b5954f411d194a60000e8353423/content.htm
for classes
http://help.sap.com/saphelp_47x200/helpdata/en/c3/225b5c54f411d194a60000e8353423/content.htm
for methods
http://help.sap.com/saphelp_47x200/helpdata/en/08/d27c03b81011d194f60000e8353423/content.htm
for inheritance
http://help.sap.com/saphelp_47x200/helpdata/en/dd/4049c40f4611d3b9380000e8353423/content.htm
for interfaces
http://help.sap.com/saphelp_47x200/helpdata/en/c3/225b6254f411d194a60000e8353423/content.htm
For Materials:
1) http://help.sap.com/printdocu/core/Print46c/en/data/pdf/BCABA/BCABA.pdf -- Page no: 1291
2) http://esnips.com/doc/5c65b0dd-eddf-4512-8e32-ecd26735f0f2/prefinalppt.ppt
3) http://esnips.com/doc/2c76dc57-e74a-4539-a20e-29383317e804/OO-abap.pdf
4) http://esnips.com/doc/0ef39d4b-586a-4637-abbb-e4f69d2d9307/SAP-CONTROLS-WORKSHOP.pdf
5) http://esnips.com/doc/92be4457-1b6e-4061-92e5-8e4b3a6e3239/Object-Oriented-ABAP.ppt
6) http://esnips.com/doc/448e8302-68b1-4046-9fef-8fa8808caee0/abap-objects-by-helen.pdf
7) http://esnips.com/doc/39fdc647-1aed-4b40-a476-4d3042b6ec28/class_builder.ppt
8) http://www.amazon.com/gp/explorer/0201750805/2/ref=pd_lpo_ase/102-9378020-8749710?ie=UTF8
9) http://www.erpgenie.com/sap/abap/OO/index.htm
10) http://help.sap.com/saphelp_nw04/helpdata/en/ce/b518b6513611d194a50000e8353423/frameset.htm