Fernwood
OS/2 shareware repository, REXX section.
LogiSoft AR
RexxBOS, OS/2 Rexx library providing complete system interface.
Netlabs.org: Rexx/OS
Intended as a new incarnation of OS/2, being completely realized using the REXX scripting language.
OS/2 REXX: From Bark to Byte
IBM Redbook describing OS/2 REXX and interfaces.
Perl OS2::REXX
Access to DLLs with REXX calling convention and REXX runtime.
REXX Tips & Tricks
About Rexx programming, mostly under OS/2. Converted from INF to HTML as of september 1998.
SCOUG
Search results: Rexx. Lots of articles.
SRE-http
Web server written primarily in Rexx. Also several Rexx utilities related to directories, GIF, TrueType, MD5/MD4/SHA-1, rsync, GZIP, Blowfish, GDIFF and other.