Here are a couple of examples.
First the form is created with the assessment criteria
Then the link to the form is shared with students (I personally love how easy it is to embed within an iWeb site). Gooogle Apps for Ed allows me to share with the entire domain at once, also.
Students submit their peer and/or self assessments and refresh their page before the next presentation
After the results are tabulated in the Google spreadsheet, I sort by student name and add an average formula if I need a numerical grade. The most valuable part, however, is sharing the honest, anonymous feedback with the students who created each project-- either digitally or just printed on paper and cut apart.
A final, less exciting use of forms is for our students to report laptop damages straight from our website and have it all automatically compiled in a Google spreadsheet for documentation purposes. The benefits here are obvious if you know my personal struggles with paperwork organization!