Different than St. Patrick's Day. A lot more cultural and business stuff, but there is still a lot of drinking. In other cities it might be closer to St. Patrick's Day, if probably smaller.

Most of the NY events are actually taking place the following weekend. The info is here: NY Tartan Week

However the Scottish Executive didn't like the the NY Tartan Week Committee's planning so they are sponsoring their events the previous week. Their info is here: Scottish Executive's Tartan Week Site

The parade was moved a week later this year because of Easter. Supposedly the SE wanted the NY committee to move the Parade to the week before Easter. That was considered to close to St. Patrick's Day (which is big here in NY). In the long run they couldn't get together and so we have two Tartan Weeks this year.