Some Sources on Tzedakah from R Gil Student
You might find interesting R. Menachem Kasdan's Yesodei Tzedakah, which I reviewed here:http:
//www. torahmusings. com/2009/07/foundations-of-cha rity/The son-in-law of the author of Piskei Teshuvos recently published a similar sefer on sections of Yoreh Deah, including the laws of tzedakah. I believe the book is titled Pesakim U-Teshuvos.R. Chaim Kanievsky's Derech Emunah is a Mishnah Berurah-style commentary on Rambam's Hilchos Matnos Aniyim.
Note from RBH
In presenting any list of material on Tzedakah, we should not forget
Beyond Tzedakah: Understanding the Torah Expenditure
from Nishma Journal
available at http://www.nishma.org/articles/journal/tzedakah.htm