Is Sikhism a mixture of other faiths?

Is it a religion in its own right or combination of other religions? There are many misconceptions floating around.

Every modern religion can be understood as a combination of previous religions.

yes... it were the Hindus who became Sikhs...as per my knowledge Sikhism was born to purify Hinduism of its evils egg. the caste system...in the holy book of the Sikhs you will find knowledge gathered from various religions....

when mu gals come in India , in our country " pitapatsThare not allowed yet but, they use to insult our ladies and par4DA prat ha get birth in all Indian religions,
Mugals treat ladies very wisely , then the founder of Sikhism was initiated this religion, they prefer to fight for them protection, different look, due to " pagdi" ets,
and 11 th guru of shik religion had announced that no body will became the owner of my "gaddi"
only follower are allowed , u only do worship of my presence in adhyatam form,
i have much matter to tell u but i hope this is quite enough

Sikhism is an independent religion . No need to get confused about it . Its pretty straight forward . It seems like a mixture of diatomic and Abrahmic beliefs , but if you Analise properly , Sikhism is all about Spirituality 'minus' Rituals .
Sikhism preaches faith in one almighty who is present in all . This calls for a tolerant monotheism , because Sikhism believes that God is everywhere , throughout the creation . According to Sikhism, God is present in his creation , yet independent of it . Sikhism preaches that all faiths are equally acceptable before God and that God can be realized by all and is accessible by all . Sikhism also believes in oneness of humanity and universal brotherhood .
Sikh Scripture says " The exalted lord created the light , all beings are of nature . From one light everything has emanated , so who is good and who is bad ?".
People from non Sikh backgrounds also come and partake free meals in Gurudwara and come to pray in Gurudwara .

In regards yo your other question , You can join Khalsa community by partaking of Avrit .

However , if you have faith in one almighty , following the teachings of 10 Sikh Gurus and read Sri Guru Granth Sahib ( Sikh scripture ) , then too you are a Sikh .

You can read an English transaltion of Sikh scripture here :
http://www.sikhs.org/english/frame.html
http://fateh.sikhnet.com/s/GurugranthSahib

You can know more about Sikhism here :
http://www.sikhnet.org
http://www.sikhiwiki.org

Formal conversion ceremony :
http://www.sikhiwiki.org/index.php/Amrit_Ceremony

Good luck , with whatever faith you follow . Different streams ( religions ) ending up in same ocean ( god )