There are some extremely useful programs that you can download for free and use on your cell phone. Most of the sites require you to register before you can use their particular tool.
If you have are able to browse the web using your cell phone, there some useful links you can bookmark.
If you have found a useful tool or mobile website, please let me know (firstname.lastname@example.org) so that I can post it on this website for others to use. Thanks.