Timelines for Jetstream2 are still uncertain at this time, so it is recommended that your research group get a startup allocation now on Jetstream1 and get a supplement for JS2 when it becomes available. Migrating to JS2 will be reasonably easy.
More information about getting Jetstream1 startup allocations is available here: http://wiki.jetstream-cloud.
More information about getting Jetstream1 API access is available here: http://wiki.jetstream-cloud.
While the Jetstream2 docs are very much under construction and are constantly changing and evolving, you may wish to bookmark these two pages for now: