As far as similarities among Islam and Sikhi, Islam & Hinduism are concerned, All these are actually monotheistic religions and believe only in one diety but Hunduism having very very old history derailed from original track and made idols of stone for their sacred personalities and started worshipping them and forgot the original path.....!

I will recommend one inter-religion scholar in India i.e. Dr. Zakir Naik having web site of www.irf.net who has written many impartial books on these issues with special reference to holy books of Hinduism, Sikhhi, Christianity, Jewism and Islam and has proved various similarities in the presence of all the relevent scholars. His CDs are also commonly available in India............You may study......and discuss.........!