:) pacman -Ss json
extra/json-glib 0.12.4-1 [0.08 MB] [installed]
    JSON library built on GLib
extra/qjson 0.7.1-1 [0.05 MB]
    A qt-based library that maps JSON data to QVariant objects
community/couchdb 1.0.2-3 [0.54 MB] [installed]
    A document-oriented database that can be queried and indexed in a MapReduce
    fashion using JSON
community/jansson 2.0.1-2 [0.03 MB]
    C library for encoding, decoding and manipulating JSON data
community/jshon 20110306-1 [0.01 MB]
    A json parser for the shell.
community/perl-json 2.27-1 [0.07 MB]
    JSON (JavaScript Object Notation) encoder/decoder
community/perl-json-xs 2.3-2 [0.07 MB]
    JSON::XS - JSON serialising/deserialising, done correctly and fast
community/python-cjson 1.0.5-3 [0.01 MB]
    Fast JSON encoder/decoder for Python
community/python-simplejson 2.1.3-1 [0.05 MB] [installed]
    Simple, fast, extensible JSON encoder/decoder for Python
community/yajl 2.0.2-1 [0.03 MB] [installed]
    Yet Another JSON Library.