I am looking to find a lawyer that is willing to take a pro bono case. How can I do such a thing

Free attorneys are provided by the counties public defenders office.  If you are not able to meet the financial qualifications you most likely will need at least some money to hire an attorney.  Criminal cases take a loy of time and energy to defend properly so it is rare that an attorney takes a case pro bono.  Hence the creation of the public defrnders office in Pennsylvania.  Many counties do have marginal rederral programs for those who arent able to get an a public defender but still have limited means.