If your image editing software does not support IPTC data then there are a number of applications available which may do the job which can be downloaded off the web. I haven't used Photoshop Lightroom myself, but it seems to fall midway between Elements and Photoshop, it isn’t cheap though. Photoshop Elements from v8 does now allow straight entry of keywords, earlier versions made keyword entry difficult. The latest version of Nikon Capture now supports IPTC data (but they charge you for it even if you buy a Nikon camera!). Two which I have used are FotoStation and iMatch which both have to be paid for, but are quite powerful and allow various batch processing functions, both are available for Mac and PC. Another powerful looking one is iView MediaPro, but I haven’t tried it. BreezeBrowser is good with IPTC info, it costs about $70 but is quite useful.
A good looking free option is XnView, an image browser that allows you to edit IPTC data (TIFFs and JPEGs and only from version 1.94) and has various batch processing capabilities, there is also a shell extension so you can see and edit details fron the Windows explorer. You could also try Zoner, quite highly regarded and supports a wide range of formats, keyword entry is via a list so can be long winded and the list might get rather unwieldy, but if you have trouble spelling then so long as you get the first instance of the word right then you shouldn’t have to worry later. IrfanView will open many formats even if there is no file extension, IPTC support is limited to JPEGs via a seperately downloaded plug-in (it can be downloaded from Tucows). Microsoft have a free programme called Photo Info which once installed allows you to enter captions and keywords in Windows Explorer, it can be downloaded from Microsoft. There are installation issues which may prevent it working without an additional patch, but it's not immediately obvious what’s going on which can be confounding. I use Windows XP, it may be completely different on Vista and 7 (parts of it may even be built in to the OS).
There is a useful list of free image viewers here, many will be very basic and may not do what you require so check first. If you have used something else and can recommend it then let me know and I will add it here. My experience is mostly with PC's and I believe many of the cheaper options above are not available for Macs. If you know of suitable software for the Mac I would appreciate your views.
If you are looking for a free photo editing programme then there is The Gimp. This is open source so does not have a great deal of support and you need to be fairly confident about installing it (and it’s a pretty big download!), but it is free. On the web site look for “Binaries for various platforms” and select the Windows, Mac or even Unix option, it does not do the file info, but see above, though be warned, if you open a keyworded, captioned picture in The Gimp the data may be stripped out again so do the data entry last. The interface is a bit clunky, but it has more features than Photoshop Elements and is a good option if you don’t already have something, use it alongside XnView and you have most of the features you would need to prepare your files for us.
Photoshop is the industry standard. If you have the money (and a fairly high spec computer) it is the best. Corel Paint Shop is a lot cheaper and apparently supports IPTC captions and keywords, but I’ve not tried it so can’t confirm this, a free trial version is downloadable at the Corel web site.
There is a very useful list of free photo editing software here.
WARNING! If the picture editing programme you select does not support IPTC data then it is quite likely that it will remove any data you have already entered or possibly mess it up in some way so as to make it un-readable. You should therefor do any captioning or keywording after you have done your changes to the picture.
