In the EU, software license resale is legal, even if explicitly forbidden by terms of any EULA or other contract imposed upon the parties. To quote the European Court of Justice's press release on its ruling in a case in Germany between Oracle and a German reseller,
An author of software cannot oppose the resale of his `used' licences allowing the use of his programs downloaded from the internet. [...] The principle of exhaustion of the distribution right applies not only where the copyright holder markets copies of his software on a material medium (CD-ROM or DVD) but also where he distributes them by means of downloads from his website.
Where the copyright holder makes available to his customer a copy – tangible or intangible – and at the same time concludes, in return form payment of a fee, a licence agreement granting the customer the right to use that copy for an unlimited period, that rightholder sells the copy to the customer and thus exhausts his exclusive distribution right. Such a transaction involves a transfer of the right of ownership of the copy. Therefore, even if the license agreement prohibits a further transfer, the rightholder can no longer oppose the resale of
that copy.
There are many such companies in the EU who resell software legally, including used OEM Windows licenses that are far cheaper than retail copies. This is, in my opinion, a fantastic thing -- but undoubtedly has been behind the trend towards time-limited licenses rather than perpetual ones, which we all arguably suffer from today.