When are you supposed to...

You also don't need to have an engagement party - i kind of feel this is a new thing! My parents and my FH's parents never heard of such a thing until the last couple of years.

We got engaged on Sept. 26, 2009 and are having ours March 6, 2010 - wedding is May 28, 2011.

Another bride mentioned it before - the only rule is whoever you invite must also come to the wedding.

We are having it at Westbury Manor - it was cheaper there then some of the restaurants that were looked into.

FH's family is paying for everything.

we got engaged July 24, 2008, our eparty was feb 28, 2009 and our wedding is oct 9, 2010.

from what I understand you want to go in the middle... we did ours a few months earlier than we should have... but thats because FMIL wanted us to do it in october/november 2008 and we didn't want to do it so early so we told her feb.

as for paying... we figured it out per person (after favors, centerpeices, food, linens, etc) and we split that total 3 ways, my parents gave a third, his parents a third and us a third... but my parents paid for the DJ separately, FILs and my father tipped everyone without us knowing/realizing.. FMIL got me the most amazing bouquet for our table. and I ended buying a bunch of extra stuff like picture frames to put on the gift table with pictures of us... and jewels for the mirrors we used in our CPs....
I think it all depends on who can afford what and how big you want the party to be.

i think my engagement party was 2 weeks after we got engaged! but it was a small bbq party. we payed for it ourselves, although parents helped out with the food!