Poster presentations are invariably a lot of work, but they can be an effective way to communicate your research to a lot of people at a scientific meeting. The commercial standards for building posters include Adobe Illustrator and Microsoft PowerPoint. I've used both previously, and wanted to weigh the open source alternatives against these. My last two posters (for the Ceratopsian Symposium and the 2008 SVP meeting) were constructed using the following software (running in Ubuntu 7.04 and 7.10, respectively).
This program (now in version 0.45.1) is a wonderful vector illustrator (and I'll be reviewing these features in a future post), but it's not at all intended to handle large amounts of text. You can forget about having any control over paragraph spacing, bullets, indents, or any of the other 2,000 things you need in order to make an attractive and readable poster. In the end, I used this program to put together some of the figures for the posters, and that's about it.
This is billed as "open source desktop publishing" software (now in version 1.3.4 or so), so I gave it a spin as the primary program for my posters. As you would expect for a desktop publishing program, you get excellent control over page size and orientation. Things started to fall apart a little once I began working with the poster text. Scribus was incredibly buggy when saving my text formatting. The superscripts in the title header (denoting author affiliations) either reverted to standard text or were applied to the entire section of text once I reopened the file. Sometimes the program crashed while I tried to reformat a section. It was not straight-forward at all to format bullet points, and it required about four layers of dialog boxes to finally get everything set. It wasn't easy to incorporate multiple levels of bullets, and I had to do a lot of manual formatting. And even then, I experienced relatively frequent crashes. After a little while I figured out what set of steps to avoid, but let's just say I wasn't terribly impressed. Resizing images was also a pain - the bounding box initially served as a clipping box, until I found the option to make the image resize with the box. I muddled through, and got two posters that looked quite good, but it was a much more frustrating and time-consuming experience than it should have been.
Back in my Windows days, I used PowerPoint as my program of choice to generate posters (after resizing the page appropriately). It just worked, and although it didn't have all the options of Illustrator, it produced some nice-looking posters. For my next poster, I'm going to give OpenOffice.org Impress (the PowerPoint equivalent) a whirl. The current version (2.3.1) allows much larger page sizes than the last version, so I think it will do the trick. Text formatting is certainly quite flexible, too. So, I expect that presentation software (like PowerPoint) will remain my choice for some time now. . .
Open source software for building a poster just isn't that mature yet, but you can build a poster without Illustrator. I would advise all but the most patient user from using Scribus for this purpose and suggest Impress as probably the best alternative at present. I am optimistic, however, that our options will get better as open source software continues to mature.