Integration with other contributed modules

Here are some notes about integration with other contributed modules. This about configuration and integration with other modules to use i18n features, but not about compatibility problems. If you have any issue about compatibility with other modules, please file a feature request on the issue tracker.

Pathauto

AFAIK Pathauto module plays nice with i18n module. In addition to that, there are some features added into i18n module to provide different path templates for nodes depending on language.

Note: this won't work for bulk pathauto operations

1. Add pathauto variables to language dependent variables in settings file, like:
$conf['i18n_variables'] = array(
..............
'pathauto_node_pattern', // General pattern for nodes
'pathauto_node_blog_pattern', // Pattern for blog nodes
'pathauto_node_story_pattern' // Pattern for story nodes
............
);
2. Set up different patterns for each node type/language on pathauto settings page (Like other variables, switch interface to set values for each language...)
3. Play!

TinyMCE

it works fine, but when setting up the paths for the visual editor to show up, the language prefix needs to be taken into account

Use
*/node/*
instead of /node/* that won't work

Event, Image, CCK...

Images, event dates and CCK fields are copied over when creating a translation of a node. It will also work for most of other content types.
For the case of images, you'll need to re-create all the translations if you update the original image file.