Sort of. Depending on where this is actually stored it can be instantaneous -- at work we have a pair of servers that serve DNS via MySQL replication, and time

Sort of. Depending on where this is actually stored it can be instantaneous -- at work we have a pair of servers that serve DNS via MySQL replication, and time from putting data into the master and seeing it in DNS is well under one second. If they're suggesting you update the .tel TLD servers with your information, the sky's the proverbial limit, but it would be possible for them to keep it pretty tight. The real problem with this is that there's no notion of ACLs or multiple viewports in DNS -- I reeeeeeeeeeeeeeally don't want any spammer who can find me@iigs.tel to be able to spam me with data from GPS me.iigs.tel records.