In 3.5 if familiar dies you cannot gain a new one for a year and a day (and also lose some exp). You can raise\resurrect\true resurrect old one for the usual amount of diamond dust (and it doesn't lose constitution or any abilities when raised).
Blackwing appearing out of nowhere in the old comics is a joke. It's supposed to represent players (and even DMs) ignoring familiars and even forgetting where they are supposed to be until they need them for a specific task. Note the very first comic with Blackwing in it