1. Actually speaking. For this, you just want to practice. Often times that's what you need. Toastmasters I've heard is great, but any chance you have to practice, just go for it. I'm a big fan of improv (I've taken the UCB course in New York while in college which is really fun!), as it gets to the principle issue: comfort. You just need to feel comfortable and part of that is really about learning how to harness your nerves. The difference in feeling between being nervous and excited may not be far apart from a physical perspective, so trying to channel those nerves and treat them as a Good Thing, is definitely what you want to do, and you're only going to get better with practice.
2. Speech writing. This is totally different, and is actually very different from something like essay writing. It's very top heavy, and this IMO can be picked up from just watching a lot of speeches. Alterations, keeping track of syllable count and sonic tricks help compose how your speech is heard, which is different from how it's understood. Learning how to get something to sound a certain way is something you don't think too much about when writing essays, but is paramount to writing speeches. In addition, learning how to format them content wise is also different from many other forms of writing. I find the best way to look at this (much like programming), is to look at existing speeches (like looking at projects), and try to understand what makes a speech 'good', and what doesn't. From Steve Jobs at Stanford to Barack Obama's Red States and Blue States (Obama really employs great melodic elements in his speeches in contrast to Jobs's more conversational story telling style) - there are many different ways to cut it, but the best is to look at what impacts you and attempt to deconstruct why.
Again, if you just want to be comfortable with speaking in public, just practice and throw yourself in there. The fear of having a bad speech is always 1000x worse than the reaction to having a bad speech. The stakes in public speaking aren't as high as most people think and often times the worst thing that can happen is boredom. I find the biggest mistake most people make is really thinking people care more than they actually do. So just go and try to have fun with it - and fake that confidence long enough until it starts to feel real :).