Yeah - the bris is "announced" because it's a big mitzva to go, and so it is considered proper not to "invite" people who are then in the position of declining the mitzva. Once you know about the bris, you are expected to go if you possibly can.
Whilst gifts are appreciated, it's your participation in the simcha that is most valued. And as for handmade, I think that's way more special than a purchased gift - unique and heartfelt.
As for what to expect - first the baby is brought into the shul/room on a pillow to great fanfare, like welcoming a special guest. It is considered an honour to do the mitzva of bringing the baby to the bris and is often bestowed upon a childless couple - the wife will bring from the mother, and hand over to her husband who brings to where the mohel is. The sandek is given the honour of holding the baby on his lap while the mohel actually does the bris, and there are brachos, then kiddush and announcing the baby's name (might not be the exact order, and I may have missed out some small details - I'm the woman who hangs out right at the back!). After that, and mazal tovs, baby is returned to his mother, and there is the seudas mitzva. Everyone finds a place to sit and washes for bread and eats (usually salads and bagels kind of food, depending on how fancy), and then maybe the father will talk about the choice of name during the meal, and afterwards there is the special bentching that has many additions praying for blessings for baby, mohel, parents, etc.
Think that's "what to expect" in a nutshell!
To all the mothers still waiting - b'shaa tova. The right time should come without too much difficult waiting, and should result in an easy birth and good health for mommy and baby!