Compiling a kernel in a ppa can take a few tricks.  Here is how I do it:

   * Grab the pristine kernel for the release you want, and/or check out a new branch for your work:

{{{
git clone git://kernel.ubuntu.com/ubuntu/ubuntu-natty.git
cd ubuntu-natty
git co -b mytest
}}}

   * <hackhackhack> and commit your changes as usual

{{{
git status | grep modified | awk -F: '{ print $2 }' | xargs git add
git commit -s -m 'My test'
}}}

   * Make sure the tree is clean and ready

{{{
fakeroot debian/rules clean
}}}

   * Now create a packaging changelog entry.  If the previous entry was 2.6.38-9.43, then I might call my test 2.6.38-9.43creds1.

{{{
dch -i
}}}

   * *Important* - copy your changelog entry from debian/changelog into debian.master/changelog.

   * Make sure that the ppa will skip module and ABI checking
     * Add the following lines to debian/rules:

{{{
export skipmodules=true
export skipabi=true
}}}
     * set skipmodule to 1 in debian/scripts/module-check, so it starts with:

{{{
#!/usr/bin/perl -w

$flavour = shift;
$prev_abidir = shift;
$abidir = shift;
$skipmodule = 1;
}}}


   * Build the kernel source package using the following command:

{{{
dpkg-buildpackage -S -sa -rfakeroot -I.bzr -I.git -I.gitignore -i"\.git.*"
}}}
(Thanks to Sarvatt and tgardner for the info about ignoring VCS files)

   * You can also test-build locally using

{{{
fakeroot debian/rules binary-generic
}}}
to save having to deal with errors when building in ppa.

   * Finally push the package to your ppa.

{{{
cd ..
dput ppa:myuser/ppa *.changes
}}}


To compile on your own system, just do:

{{{
fakeroot debian/rules clean
fakeroot debian/rules binary-generic
}}}

or if you also need ddebs (thanks Sarvatt):

{{{
fakeroot debian/rules binary-generic skipdbg=false
}}}