Windows SharePoint Services V3 and Microsoft Office SharePoint Server 2007 are now be able to get updated to the latest available bits with April CU.

WSS:

2799869 The full server package for WSS
http://support.microsoft.com/default.aspx?scid=kb;EN-US;2799869


MOSS:

2799867 The full server package for MOSS
http://support.microsoft.com/default.aspx?scid=kb;EN-US;2799867

Download and installation information:
- Install SP3 for WSS and MOSS SP3 and Language Packs if not yet happened.
- Install the full server package for WSS http://support.microsoft.com/hotfix/KBHotfix.aspx?kbln=en-us&kbnum=2799869
- Install the full server package for MOSS http://support.microsoft.com/hotfix/KBHotfix.aspx?kbln=en-us&kbnum=2799867

After applying the preceding updates, run the SharePoint Products and Technologies Configuration Wizard or “psconfig –cmd upgrade –inplace b2b -wait” in command line. This needs to be done on every server in the farm with SharePoint installed.

Similar post from my colleague Stefan Gossner: http://blogs.technet.com/b/stefan_gossner/archive/2013/04/10/april-2013-cu-for-sharepoint-2007-has-been-released.aspx