Using organizer software is one of the great advantages of a computer, but before choosing a suitable one it is a good idea to think carefully about what you really need...
One of the most popular organizers world-wide is EssentialPIM. It is very easy and simple yet contains a diary, address list, and notes section. The downside is it takes quite a lot of system resources, which can be unnecessary unless you actually need all its facilities. It may be better for you if you use smaller utilities just for the facilities you need.
http://www.ezoutlooksync.com/
Some alternatives are...
Chaos Manager. Same facilities as EssentialPIM but much smaller. Alas, not as user friendly, especially in the diary.
http://www.chaosmanager.net/
Calendar. Just a simple calendar program, but does its job very well, and very low on resources. Does not include alarms though.
http://www.geocities.com/calendarprogram/
ShirusuPad. Very low resources, sits in tray. A sort of cross between a notepad and post-it notes, and includes reminders alarms and to-do lists. Has been known to crash occasionally if an alarm is shut off too quickly, but aside from that its an excellent product.
http://www.shirusupad.tk/
ATNotes. Been around a long time - one of the better post-it notes programs. Just simple yellow notes, but does include facility to send them as messages around a local network.
http://atnotes.free.fr/
WireNote. In some ways similar to Shirusupad yet this one is more resource-hungry. But its worth trying out because of its immense power. Aswell as notes and to-do lists, it includes various messaging systems for Lan and can receive your emails too. For multi-users there is also a bulletin board.
http://www.wiredplane.com/en/commons/download.php
The Clock. Although there are many graphic desktop clocks around, they tend to use much system resources. This one doesn't. The clock is re-sizeable and includes alarms and timer. It also can be set to chime on the hour and every 15 minutes. The display can be semi-transparent (on 2000 and XP) but also can allow you to "click-through" as if it wasn't actually there. You have the option to keep it above other programs too.
http://go.to/thexagon
PowerMenu. A utility that adds menu items to all windows when you right-click on a title bar. Includes the most useful facility of all - to keep any window on top of others.
http://www.veridicus.com/tummy/programming/powermenu/
HiddenMenu. A low-resource alternative to the clunky Start Menu. The appearance is nothing to shout about, but it does its job fast and is very well behaved.
http://ideasoft.hp.infoseek.co.jp/file/hiddenmenu22.exe
HoverSnap. An extension to the "Print Scrn" key. It hooks into the key to alter the way it works. It allows you to automatically save screen images to files, rather than having to paste them into a graphics program from the clipboard. The change it makes is not permanent, so no need to worry there - close HoverSnap and everything goes back to normal.
http://www.hoverdesk.net/
WindowSize. Sometimes you might be designing something, such as a website, and want to see what it will look like at another screen size. Changing the screen resolution can be a pain, especially if you need to do it continually. WindowSize solves the problem by allowing you to instantly resize any window to the exact size it would be at another resolution. And it is very accurate, allowing for things such as the taskbar size.
http://www.markuswelz.de/freeware/index.html
1stQres. Another commonly needed facility is to quickly see how something would appear at a different color resolution. If you design something in hi-color, it can look very odd in 256 color mode. 1stQres is a fast way to switch color resolution - and back again, without having to go through multiple dialogs or the control panel.
http://www.greenparrots.com/aqr.html
MagicDsk. Ever wondered what your computer would be like without the desktop icons? You wouldn't want to get rid of them permanently, but MagicDsk allows you to instantly hide or show them from a tray click.
magicdsk.exe
WeatherWatcher. There are many weather forecast downloaders around, but unfortunately most seem to download far more than needed, and some adverts too. This program shows you just how much you didn't need - it gets you a full detailed forecast for 10 days by downloading only about 6k of data. If you want a satellite map too, its only about another 10k. This is what a weather program should be like - no bells and whistles, just the weather data you want to know.
http://singerscreations.com/