Sorry I've not had a chance to look at the code yet (where have you uploaded it to)?
Setting arbitrary update intervals is a must IMO,
and it would also be useful to be able to tell it to only use an existing connection (e.g. so you can leave it running when abroad and not worry about roaming) or specify which connection types it is allowed to start itself.
If there's already a connection up, being able to set a different update interval would be useful (if the connection is there anyway why not update position) but again having it user configurable would be good as the GPS chipset is a power drain so the user should be able to decide how often it's run.