With end of July 2010 support for Oracle 10g Release 2 ends. You can order (at additional costs of course) so called extended support to get support until July 2011. After this date there is so called “Sustaining Support” which offers support for several more years.
Update: I was told the first year of Extended Support is free of charge (Thanks Martin!). So customers have a little bit more time to test and upgrade.
See the following picture for the support end dates:
So if you start with new projects i´d strongly recommend to use Oracle 11g Release 2 at best or if 11g R2 is not an options 11g R1.