Short urls, do they pass some PR?

I'm going to spread my content using microblogs from ping.fm and hellotxt, but I have some questions about short urls

do they pass some PR? do they help to SE indexing? is there some free short url service better than another?

some feedback would be fine

As long as it's a 301 redirect (not a meta redirect or something like this) I think they pass link juice / help indexing, etc.

I'd stay with the most known ones like bit.ly

is there some way to check what kind of redirect use? I run a shor url service, but cannot find out what kind of redirect uses