Well I suppose it depends what sort of statistical analysis you wish to use. But for comparisons of percentage cover of vegetation I have always used IBM SPSS, you can just load an XL spreadsheet into it, select your analysis and away you go! If it’s just a one off thing then you can get a 14 day trial here: http://www14.software.ibm.com/download/data/web/en_US/trialprograms/W110742E06714B29.html
Hope that helps!
EDIT: If you are unsure on what analysis to use you can do some googling but I found how2stats' videos on youtube very helpful; maybe look at ANOVA's and t-tests to get a grip with it.
