Wiki Calc would be excellent (however, it's written in perl, afaik)
Tikisheets (in 1.10) IS the solution for newbies. Export from OOo or M$ Excel as csv (not the .xls-dev which doesn't work), and go ahead.
I've been using it with (non-tech) students for a year with great success when tables where not bigger than aprox. 30 columns and rows.
I made this short help page for this tasks (in catalan, but screenshots my help)