Susanwill,
If you're pursuing an immigrant visa the old packet terminology really doesn't apply any more. You're going to receive more mailings than 2, several of them coming from the NVC rather than the consular section.
But to answer your question in simplistic terms, packet 3 is the visa application packet and packet 4 is the visa interview packet.
Yodrak
QUOTE(Susanwill @ Nov 3 2006, 01:54 PM)

Hi,
For those of you who have received packet 3 & 4 what do these packets entail?