http://msdn.microsoft.com/en-us/library/ms476046(office.12).aspx
Sharepoint provide several tokens:
(1) Two dynamic tokens — ~masterurl/default.master, ~masterurl/cutom.master, Master à Dynamic
Example — <%@ Page MasterPageFile=”~masterurl\default.master”%>, the token “~masterurl/default.master”
is replaced at run time by the value in the MasterUrl property.
The token “~masterurl/custom.master”
is replaced at run time by the value in the CustomMasterUrl
property
(2) Two
static tokens — ~ site/default.master, ~sitecollection/default.master, Site à Static
You can use these tokens to link to a site-relative or site collection-relative master page.
For example, if your content page is located at http://siteColl/subsite1/subsite2/default.aspx and you use the token “~sitecollection/mypage.master”, your content page would use the master page at http://siteColl/mypage.master. If you use the token “~site/mypage.master”,
the content page would use the master page located at http://siteColl/subsite1/subsite2/mypage.master.
You can add static Web Parts (not in a zone). Nothing else.