I've been working on a PhpMyAdmin-like tool recently called Schema (http://github.com/timdavies/schema). It's a single-page app (Node.JS/Backbone) and I've had quite a bit of positive feedback from people testing it - much faster than PhpMyAdmin, nicer UI, etc. There's a lot left to do on it (missing critical features at the moment such as inserting rows..) however I'm unable to work on it for roughly a month as I've taken a new job and need to learn some new stuff for it. If anyone wants to help out, you'd be more than welcome (will give commit access after a few pull requests) :-)
It is built with GWT. It does not have a standard FOSS license since it is not (yet) open source. The license is included with the download, it still fairly standard, the product is free no strings attached.
I use Racket which comes with a ton of features that let me build larger systems. Other more pure Scheme systems like Guile also have the capabilities to build modules/libraries, etc... and there is a decent amount of code out there to do stuff. You do have less of a choice for certain things than languages like Perl or Python, but most modern Schemes or Scheme-like languages are pretty good.
Most large-ish Scheme systems have a module system. You're a bit limited if you stick with straight R5RS, but even then every serious compiler/interpreter has additional features. Not unlike Python, Perl, Ruby, PHP, etc. There is also R6RS and R7RS now, which have additional features now.
I'm planning to get one sorted soon, just very busy at the moment and don't have much time to dedicate to the project. I've got the domain getschema.com and will put something on there when I get the chance.
