From IICM

This is an overview of the interwiki table. Meanings of the data in the columns:

Prefix	Interwiki prefix to be used in [[prefix:pagename]] wikitext syntax.
URL	Template for URLs. The placeholder $1 will be replaced by the pagename of the wikitext, when the abovementioned wikitext syntax is used.
Forward	An http request to the local wiki with this interwiki prefix in the URl is:
no	not honored, usually blocked by "page not found",
yes	redirected to the target URL given in the interwiki link definitions (i.e. treated like references in local pages)
Transclude	If wikitext syntax {{prefix:pagename}} is used, then:
yes	allow transclusion from the foreign wiki, if interwiki transclusions are generally permitted in this wiki,
no	do not allow it, rather look for a page in the template namespace.

See MediaWiki.org for more information about the interwiki table. There is a log of changes to the interwiki table.

Prefix	URL	Forward	Transclude
cache	http://www.google.com/search?q=cache:$1	no	no
commons	http://commons.iicm.net/~iicmnet/commons/wiki/index.php/$1	yes	no
dictionary	http://www.dict.org/bin/Dict?Database=*&Form=Dict1&Strategy=*&Query=$1	yes	no
google	http://www.google.com/search?q=$1	yes	no
imdb	http://us.imdb.com/Title?$1	no	no
mediawikiwiki	http://www.mediawiki.org/wiki/$1	no	no
metawiki	http://sunir.org/apps/meta.pl?$1	no	no
metawikipedia	http://meta.wikimedia.org/wiki/$1	no	no
slashdot	http://slashdot.org/article.pl?sid=$1	no	no
sourceforge	http://sourceforge.net/$1	no	no
sociologue	http://sociologue.iicm.net/~iicmnet/sociologue/wiki/index.php/$1	yes	no
press	http://press.iicm.net/~iicmnet/press/wiki/index.php/$1	yes	no
corps	http://corps.iicm.net/~iicmnet/corps/wiki/index.php/$1	yes	no
context	http://context.iicm.net/~iicmnet/context/wiki/index.php/$1	yes	yes
console	http://console.iicm.net/~iicmnet/console/wiki/index.php/$1	yes	no
apept	http://apept.iicm.net/~iicmnet/apept/wiki/index.php/$1	yes	no
zipcode	http://zipcode.iicm.net/~iicmnet/zipcode/wiki/index.php/$1	yes	no
wikia	http://www.wikia.com/wiki/$1	no	no
wikibooks	http://en.wikibooks.org/wiki/$1	yes	no
wikicities	http://www.wikicities.com/index.php/$1	no	no
wikif1	http://www.wikif1.org/$1	no	no
wikihow	http://www.wikihow.com/$1	no	no
wikinfo	http://www.wikinfo.org/index.php/$1	no	no
wikimedia	http://wikimediafoundation.org/wiki/$1	no	no
wikiquote	http://en.wikiquote.org/wiki/$1	yes	no
wikinews	http://en.wikinews.org/wiki/$1	yes	no
wikisource	http://sources.wikipedia.org/wiki/$1	yes	no
wikispecies	http://species.wikipedia.org/wiki/$1	yes	no
wikitravel	http://wikitravel.org/en/$1	no	no
wiktionary	http://en.wiktionary.org/wiki/$1	yes	no
wikipedia	http://en.wikipedia.org/wiki/$1	yes	no
college	http://college.iicm.net/~iicmnet/college/wiki/index.php/$1	yes	no
coach	http://coach.iicm.net/~iicmnet/coach/wiki/index.php/$1	yes	no
w	http://en.wikipedia.org/wiki/$1	yes	yes
culturescape	http://culturescape.iicm.net/~iicmnet/culturescape/wiki/index.php/$1	yes	no
Commons	http://commons.iicm.net/~iicmnet/commons/wiki/index.php/$1	yes	no
Apept	http://apept.iicm.net/~iicmnet/apept/wiki/index.php/$1	yes	no
Coach	http://coach.iicm.net/~iicmnet/coach/wiki/index.php/$1	yes	no
College	http://college.iicm.net/~iicmnet/college/wiki/index.php/$1	yes	no
Console	http://console.iicm.net/~iicmnet/console/wiki/index.php/$1	yes	no
Context	http://context.iicm.net/~iicmnet/context/wiki/index.php/$1	yes	yes
Corps	http://corps.iicm.net/~iicmnet/corps/wiki/index.php/$1	yes	no
Culturescape	http://culturescape.iicm.net/~iicmnet/culturescape/wiki/index.php/$1	yes	no
Cyclopedia	http://cyclopedia.iicm.net/~iicmnet/cyclopedia/wiki/index.php/$1	yes	no
IICM	http://institute.iicm.net/~iicmnet/iicm/wiki/$1	yes	no
Press	http://press.iicm.net/~iicmnet/press/wiki/index.php/$1	yes	no
Sociologue	http://sociologue.iicm.net/~iicmnet/sociologue/wiki/index.php/$1	yes	no
Zipcode	http://zipcode.iicm.net/~iicmnet/zipcode/wiki/index.php/$1	yes	no
cyclopedia	http://cyclopedia.iicm.net/~iicmnet/cyclopedia/wiki/index.php/$1	yes	no
iicm	http://institute.iicm.net/~iicmnet/iicm/wiki/index.php/$1	yes	no
mw_commons	http://commons.wikimedia.org/wiki/$1	yes	no