Read about the International Transgender Day of Remembrace. Stats and other info here.
Some blogs to read:
genderbitch's I Will Not Forget Them
Chally at Zero at the Bone
meloukhia at this ain't living
kaninchenzero at FWD/Forward
Also, Queen Emily's post from 2008 on how to mourn
If you want to know who is being mourned, here's a list. Please note it is by no means a comprehensive list.
Arwyn says lots of good things here, especially for us cis folk. Read, learn, remember, act.
If you are on Twitter, you need to follow the ladies I linked above, as well as nueva_voz (when I checked her blog she didn't have a TDOR post, but if she posts one I'll update the links).
This article is also a good read (any day of the year).
And now, I'm going to sit my white(-looking) cis a$$ down and let these women mourn in peace.
From jaysays.com: Transgender Day of Remembrace 2009: The Exclusion Question Answered