Navigation going diagonal!?

hi,

we’re doing a CSS website (first one) and they’re asking us to do our navigation in a way which i suspect may be odd and dumb, but oh well.

basically i’ve made a <ul> for the different links, then i’m adding b/g images to the list items for buttons…

however when i put them to inline and float them, IE does this weird thing where it makes them go diagonal (see screenshot). I can’t work out why, FF seems fine.

any ideas, couldn’t find a tute for it.

thanks
Stuart