view/show guides will show the slice guides.
slice is a python fu script so you need the python packages installed to use it.Get the entire Python install files here.
http://photocomix-resources.deviantart. ... rt-easie...
Slice comes packaged with 2.6 versions of Gimp.So if you have these python files installed it will be there.
make sure to read the install instructions very closely and follow them correctly.It is very important that you uninstall and reinstall Gimp 2.6.10 after you install all these Python files.Gimp will then let you click a customize button during install and give you the Python option.
Follow the instructions and you will have many many more great scripts in your arsenal through Python. =)
If that doesnt work for you, send me PM or email
[email protected] the PSD and i will slice it for you.