tzconvert converts timezones using TimeZone Converter service.
If you don't know the string defining a timezone, you can type as well the user friendly city name. The local time is the default and is expressed as a GMT offset.

Examples:

tz 10am from pst to gmt+1
tz from new_york to london
tz 12am from rome to new_york
tz to london
tz from tokyo

As usual there is the command documentation in illuminated code format.

Other Ubiquity commands:

yahoo-graph
aptana-search
fxconvert