- If these training are business or IT (infrastructure) minded :
All the core concepts you'll gain in training sessions are still valid in SharePoint 2013. By the time you fully understand the concept of farms, web applications, service applications, security, site collection, content types, fields, list, libraries, etc. you'll have a much clear view of what SharePoint is and will only have to understand the delta between 2010 and 2013. SharePoint 2013 UI will be slightly different but is still around the concept of the ribbon & the site action (although it's a little gear now !)
- If these training are targeted to developers (and you'll implement solution in the 2013 way) :
I would wait for official 2013 trainings, as the app model / concept is quite different to farm solutions usually described during them.
In both case, I would heavily recommend relying first on good books (eg : for SharePoint 2013, you know have the Wrox - Beginning SharePoint 2013 book which is well worth the little amount of money invested for end / business users) and then complete specific unclear area by following specialized training sessions.
Edit : and you can get all the nice presentations for the official conference : http://mssharepointconference.com/Pages/default.aspx for a low price (200$ at the time of writing, much less than any training !)
