Antivirus experts have found an odd virus that attacks Delphi library units to get compiled into your programs. The W32/Induc-A virus doesn't affect executable files, but looks for a Delphi installation (apparently versions 5, 6 and 7), modifies SysConst.pas (backing up the original) and gets compiled by Delphi into your own programs, to keep spreading.
You can find an overview at this c|net article, this Sophos Lab blog entry, and this one as well. To find more detailed information, though, you can look at the description on www.viruslist.com/en/weblog?weblogid=208187826 (this blog post includes the injected source code).
In the CodeGear newsgroups there are already several developers who have been infected over the last 3 or 4 weeks, simply by testing utilities written in Delphi and downloaded from the web. Given the popularity of Delphi as a development tool for utilities, this is probably a fairly common scenario.
So if you are still developing with an old version of Delphi, beside recommending that you upgrade your development tool, I suggest you run a good antivirus program, or some of the users of your programs might get virus warning, which are not false positives, as happens from time to time with Delphi applications, but real virus alert even if lightweight ones, as the virus seems to spread but not cause any other damage.
Another way to check you system, according to reports, it to look at the timestamp of SysConst.dcu, under the lib folder, or check if there is a sysconst.bak file in the same folder.
I'm not sure if this is something to be happy about in this scenario, but given the huge number of Delphi free and shareware programs available, there is a good chance this virus spreads. So, please, let all your fellow Delphi developers know about this (even if mild) threath. And suggest they upgrade ;-)