If your linux system is supported by a major distribution and has been regularly updated,
then it should have picked up and applied the new daylight savings patch.

You can check by running the command:

/usr/sbin/zdump -v /etc/localtime  | grep 2007

and looking for the output:

/etc/localtime  Sun Mar 11 06:59:59 2007 UTC = Sun Mar 11 01:59:59 2007 EST isdst=0 gmtoff=-18000
/etc/localtime  Sun Mar 11 07:00:00 2007 UTC = Sun Mar 11 03:00:00 2007 EDT isdst=1 gmtoff=-14400
/etc/localtime  Sun Nov  4 05:59:59 2007 UTC = Sun Nov  4 01:59:59 2007 EDT isdst=1 gmtoff=-14400
/etc/localtime  Sun Nov  4 06:00:00 2007 UTC = Sun Nov  4 01:00:00 2007 EST isdst=0 gmtoff=-18000

If you see Apr 1 instead of Mar 11 then you ARE NOT set for the new rules.

If you are not set then look around for a manual patch for your distribution (If you built it yourself, then
you are probably good enough to patch it yourself.)

e.g. for redhat based systems:

mkdir timezone
cd timezone
wget http://www.mirrorservice.org/sites/www.ibiblio.org/gentoo/distfiles/tzdata2007c.tar.gz
tar -xzvf tzdata2007c.tar.gz
mkdir zoneinfo
/usr/sbin/zic -d zoneinfo northamerica
cd zoneinfo
su
cp -r * /usr/share/zoneinfo/

You now need to have this new info moved into the /etc/localtime database.
The easiest way to do this is to change time zones twice, once away from where you are (Eastern USA)
and then back.  During this last step the new info in /usr/share/zoneinfo/ will be read into /etc/localtime.
The (gui based) redhat tool is redhat-config-time or system-config-time.

Check with
/usr/sbin/zdump -v /etc/localtime  | grep 2007
again.