New Travel Tool from Google
 

Google has developed a internet tool to search how to get anywhere by public transit.
It's still in the beta stage so buggy but appears to work well.

http://www.google.com/transit

Yeah, this is a nice tool - I've been using it for over a year. Portland was the first city they started testing it on; good to see they've now added other cities.

I also use www.hopstop.com for NYC, Chicago, etc.

I just tried mapping out a route I will be taking in Chicago next week using hopstop.com

I'm glad there is an easy online resource to help me determine the appropriate bus, but it would be more helpful if it also included the distance I will be travelling during the walking segments.

Just mentioning cross-streets is not helpful to a non-Chicago native!

Okay, maybe I was a little hasty. I mapped out another Chicago route and WAY down at the bottom there is a break-out of distance for each segment.

The 360 degree view option is pretty cool.

Hopstop for the Washington, DC Metro unfortunately omits all the Metro stops in Arlington entirely!

I've also used hopstop, but I always cross check with each city's transporation site - I find most major cities today - Chicago, Washington, DC, Boston - all have trip planners for buses/subway/trains on their city transit home page -

for walking directions I use hopstop/google and still usually double check with someone before leaving my hotel.