So what do all these announcements mean...?

Hi all, I've made a bit of money in the stockmarket so far this year, but still have a lot to learn. The company announcements are one thing I'd like to understand better.

For example, taking some announcement headlines from various companies:
"Appendix 3B" comes up a few times; no idea what any of that means.
"Change of Director's Interest Notice" - is this a good thing or a bad thing?
"BHP Billiton Plc - Transaction in Shares" - this comes up a lot for BHP, does it mean anything significant?

Can anyone shed some light on those? There's probably thousands of others, but I don't want to turn this post into an essay. Feel free to add and explain any important ones to watch out for. Thanks!

Appendix 3B: Whenever new shares are issued, one of these is announced. Can be from conversion of options, or capital raisings. Company is allowed to raise small amounts of capital each year (<15% i think) without share holder approval. Anything bigger must be share holder approved.

Change of directors interest: whenever a director buys/sells shares, or is given shares for performance etc. one of these is issued.
Direct - director has bought or sold in his/her name. Indirect - can be a spouse or a related company.

A director buying or selling can be an indicator of the director's opinion of share price, can be an indication of inside knowledge (not supposed to be though). Mostly however it shows the director's aren't much good at valuing thier company either.

Transaction in shares: BHP is doing a share buy back - bhp is telling investors how much it has bought and at what price. The transaction in shares terminology seems to be a LSE requirement (bhp is dual listed on asx and lse (and NYSE and possibly others)). ASX only listed companies seem to announce "daily share buyback" notices (see AMU).