This is very good news. Only last month a company by the name of Tripwire announced that they were going to distribute Red Orchestra over steam. Though a little off topic, Red Orchestra is a first person shooter that strives to convey a realistic partial of war on the eastern front. It’s well worth checking out if you own a copy of UT 2004.
Anyway, getting back on topic this is good news because developers will have more control of content and release dates, so no more rushing games with bugs to the shops in order to please distributors. This should lead to higher quality games with less bugs. Also patching a game is much less of a headache as it’s automatic so any bugs that inevitably crop up will be dealt with very quickly and easily. Also given that there would be less overheads such as distribution and production costs this might lead to a reduction in price or if not that more money for funding other simulations and/or expansion packs. Good news indeed
Edit:
http://www.pczone.co.uk/news/news_story.php?id=126707
"The publisher's first Steam release will be submarine sim Dangerous Waters, which will debut on the service later this month, although eventually Steam users will be able to purchase and download a variety of Strategy First's games releases."