This is all alpha. All code should be regarded as likely buggy, a lot of features aren't yet implemented, all protocols are likely to change in non-backwards-compatible ways.
That being said, there's a lot of code written, and I'm at the point where some feedback could be very helpful. The core functionality is all there, and it all seems to work, at least in the "sunny day" case. That is, one can create mints, issue coins, trade them with other traders, exchange them from the mint with new coins, and so on.
The error cases aren't really handled at all yet. Entities will refuse an entire payment if any of the coins are invalid (either because of bad signatures or because they're aleady spent), but it's not really clear to me what should happen after that. I think it's a good idea to have a reply file format that lists which coins are defective and what is allegedly wrong with them, but I haven't made one because it isn't clear what to do with it.
The client-server protocol is completely a placeholder. I had to put in something, but I already have some better ideas how it could be done. Right now I'm thinking the client should send something like a cgi query string, and the reply from the server should always look like a table (maybe a table with just a header, one column, one row). Maybe other people will have better suggestions.
The most important thing to nail down is the protocol by which the amint servers talk to each other (payment files especially). Until future revisions can be guarenteed backwards compatible the system will be stuck at toy status.
I'd like to make something like a browser plug-in so that a web page could easily offer content in exchange for "coins".
The gui client needs lots of improvement.