a few weeks ago we configured jboss.org JIRA instance (issues.jboss.org) to allow remote linking of issues with Hibernate JIRA (hibernate.onjira.com) and Apache JIRA (issues.apache.org/jira). This feature allows better linking of issues with upstream/downstream project issues. Linking with Hibernate JIRA is bidirectional, so you can link from Hibernate JIRA issues to jboss.org issues too. Linking with Apache jira is possible from jboss.org JIRA only, linking is not configured on Apache jira side.
The feature is available from common jira issue Link action. Linking dialog now contains new field called "Server", where you can specify JIRA server you want to link issue from. Then you can directly type in issue key from selected server, or search issue against the server.
Details about JIRA remote issue linking are available in JIRA documentation.
jboss.org JIRA instance has been updated this Wednesday to bring latest version of JIRA and other installed plugins and some bugfixes as you can see in release notes.
JIRA point upgrade from 5.2 to 5.2.5 brings mainly bugfixes and performance improvements. One noticeable change is move of reports from dropdown menu to the panel on the Project Summary page, so they are more accessible now.
GreenHopper has been upgraded from 6.0.8 to 6.1.1 which brings few new features and enhancements. Main enhancement is introduction of Epics, which provide you with an additional hierarchy of story management, providing planning guidance for groups of issues within, or across, projects. For details see 6.1 and 6.1.1 release notes.
Balsamiq Mockups plugin for JIRA has been upgraded from 2.2.2 to 2.2.4 which brings support for linking to web addresses (URL's) in all controls that support linking and other improvements and fixes. See relese notes for full list of changes.