We've already got ParseMoney in util.cpp, this patch adds parseNumber/uriParseAmount. Having more than one way to convert strings into bitcoin amounts is not a good idea, in my humble opinion.
Also, instead of having a separate executable it would be more 'wxbitcoin-like' to have one executable that acts as either client or server depending on what command-line arguments are given. The problem with two executables is you'll have clueless users double-clicking on bitcoinuri.exe and then wondering why it doesn't do anything.
I do like the use of boost message queues to communicate.