Help with posting XML

i am trying to use the online tools provided by UPS to calculate
shipping information. i’ve read a lot about creating web services on
rails using REST but when it comes to web services on the client end,
i’m not sure where to start.

all i need to do is post an XML string and parse the response i get
back, which sounds easy to me, but i’m having trouble finding any ruby/
rails specific examples of this being used.

does anyone know of some resources that will help? thanks.