EDIT: Thanks for your very useful answers, everyone!
I was typing the original post in haste, and left out a few vital details:
PvP is okay in our campaign, as long as it is reasonable and in character. Also, the bard character I killed and my character have had very long-running animosity. The player was okay with his character being killed (after the fact. He didn't know it was coming beforehand) and is currently working on a new one (further note: the bard character was also evil [Lawful Evil]).
I play as Neutral Evil Dread Necromancer and, generally, am a bit of a jerk. My character enjoys animating corpses into undead, though doesn't necessarily take huge enjoyment from doing the killing himself.
Anyway, the Bard of our party fell down a huge pit trapped which left him near death. I had an item at the time that allowed me to tunnel through dirt and stone, so I went to see how he was. Finding him nearly dead, I offered to save him if would repay me. He declined, so I killed him and animated him.
As you can imagine, the rest of the party isn't very happy. They're also metagaming (as they couldn't see it happen) A LOT. So, a couple of them are basically out for my blood (unreasonably, considering their characters) and I'm not sure how to survive past the next few sessions. I'm level 8.
Any ideas?