I think what you're looking for is a conversion into the Khalsa panth. There is actually no 'conversion' process for becoming 'a Sikkh'.
A Khalsa warrior is one who dedicates his or her life to the service of humanity by suscribing to a regime of emotional and physical discipline as outlined by the Tenth Guru. It is not a path for everyone, as it demands a lot of a person. Of course, one who is truly devoted to any discipline will find it much easier, but let there be no illusions about the fact that this is a path the width of a sword's edge.
The ceremony by which one joins this 'Brotherhood of Humanitarian Knights', as it were, is a process referred to as "taking amrit", which involves the recital of certain prayers and the drinking of a particular type of water known as amrit, which is essentially just water with sugar mixed with a steel blade.
It's actually a very deliberate political and ideological statement by the Tenth Guru, in which he replaced the ceremony of people drinking the water in which the feet of a Gurus or Sant of the old whom they followed would have been dipped. Guru Gobind Singh Ji was essentially saying "worship only the power of the sword, for it has the power to change destiny" by dipping the blade into the water instead of the ritualised (and wrong) dipping of feet.
The Sikkh community at large as you probably see and understand it undergoes no ritual of 'baptism', however. I suppose you'd just go to the Gurudwara regularly and listen and absorb gurbani.
It may be of interest for you to know that nowhere in the Guru Granth Sahib is the keeping of hair or the formation of the Khalsa mentioned. It is mentioned only in the Dassam Granth; a volume whose authorship and authenticity is still highly debated, but whose devout followers are the Khalsa of today. The Tenth Master never dubbed this volume as a 'Guru' as he did the Granth Sahib, and I think it's very important that people recognise his choice in doing so. It has always occured to me that the Khalsa is a cult of Knights created for a specific purpose. Whilst it contradicts certain passages in the Granth (such as the useless nature of wearing particular clothes, or the uselessness of the keeping of hair), it is a 'necessary evil' in that it allowed these Knights to rally around a particular image (that of a Khalsa) and to allow this to invigorate their fighting spirit to preserve the text that would preserve humanity's freedom.
They were the isolated and often violent shell comprised of men and women who sacrificed their lives to this way of life in order to protect the universal and peaceful philosophy of the Granth, and who took it upon themselves to fight for those who could not fight for themselves.
