Call web service in excel
Yes You Can!
I worked on a project that did that (see comment). Unfortunately no code samples from that one, but googling revealed these:
How you can integrate data from several Web services using Excel and VBA
STEP BY STEP: Consuming Web Services through VBA (Excel or Word)
For an updated answer see this SO question:
calling web service using VBA code in excel 2010
Both threads should be merged though.