I downloaded Squeak, the Image file, and the Sources file, but I can't figure out how to write Smalltalk code. Is there something obvious I'm missing? Is Squeak even the right IDE for serious Smalltalk development?
Hopefully, this will help you: http://wiki.squeak.org/squeak/377
This as well: http://www.cosc.canterbury.ac.nz/wolfgang.kreutzer/cosc205/smalltalk1.html
These videos are a nice simple introduction to Squeak especially this one.
I don't think Squeak is really oriented towards "serious Smalltalk development". It's intended as a first programming environment for children. Which isn't to say that you can't do useful stuff with it, it's just not aimed as much towards large-scale development.
Check out the Wiki for getting started tips. It's been a while since I last used Squeak, but I don't remember it being particularly hard to get started.
Squeak is a great environment for learning Smalltalk, but don't confuse that particular implementation with 'Smalltalk'. Some of the other implementations are very professional, but not surprisingly come at a financial cost.
Squeak is an excellent IDE for serious Smalltalk development. That is not to say that it cannot be improved. The pharo guys are eleminating from the squeak image the parts you might not want for professional development.
Download (or buy) the book Squeak by Example to get started.
Get yourself a copy of Squeak by Example.
Either as a free PDF or as a book.
Squeak is nice to learn the language and to see how creative a system like it can make people, which has two aspects: you see many interesting ideas and new concepts tried, but also a lot of junk and bad looking (some even abandoned) experiments.
I admit that, for a beginner, it may be hard to see the big picture, or if there is any at all. An example is the use of multiple GUI schemes (MVC vs. Morphic): at a time, where the mainstream is junping on MVC (they just understood in Java, what the ST guys talked about 20 yrs ago, and so they went from callbacks and AW to Swing), the Squeak guys are fed with MVC and move on, trying other aproaches. There is also a lack of "professional look" in squeak. And a chaotic community, some of which are quite ego-driven individuals.
It can be argued, if Squeak alltogether is good or bad for Smalltalk's reputation, as it certainly pisses of all those who want to write "conservative" windows apps, with menubars, icons, toolbars etc. Also performance used to be a problem (but since ELiot is working on the VM, is getting better...)
On the other side, there are wonderful applications, which are almost impossible in other environments: look at croquet (having a browser on the wall, with fishes swimming around), Etoys, Scratch, nice Seaside apps etc. And also almost all things which are now considered mainstream have originated from the Smalltalk and the Squeak community. And these guys are moving on...
So please take a look at the other Smalltalk's too: there are at least GNU-ST, Visualworks and Smalltalk/X. The later two are more biased towards blassical business apps, and the language and base libraries are almost the same. VW is not free, for commercial work, though.