The Software Updates Monitor (SUMo) is an easy-to-use tool that will quickly scan your PCs installed applications, and let you know if any have updates available.
To give the program a try, just run it and wait while SUMo builds a database of your software. Then click the Check button and it will go online, compare your installation with the latest version that's available, and highlight any programs that are out of date.
If you've a lot of software installed then this can make for a lengthy report, but fortunately SUMo makes good use of colour coding and icons to help make the relevant information stand out. And so anything with a green tick icon is up-to-date; programs highlighted with a yellow start have only a minor update available; and any software with an orange exclamation mark should really grab your attention, as that means you're at least one whole version out of date.
Once you've identified a program you'd like to upgrade, then, you should select it and click the Get Update button. This won't take you to the author's site, unfortunately, but you can search the web or various download sites for the program in just a few clicks, and so should be able to track down the update fairly quickly.
Please note that an increasing number of security tools regard SUMo as containing spyware as it ships with "Relevant Knowledge". See http://www.kcsoftwares.com/?rk for more info.