I'd say it is there...what you did, removed the bootloader which handles linux too (lilo or grub?)
what you need to do now, is find a bootdisk (floppy or cd-rom, which enables you to start up your linux...some of today's install-cd's let you mount partitions and install stuff using them...) and get somekind of shell working. when you get it, just re-install grub or lilo and configure it so that it knows all your operating systems and where they reside..
after this, just boot
Windows has a nasty habit of removing other bootloaders without asking, if one has installed such a thing into MBR or to a place where Windows usually does too. (the solution would be to create an own partition for bootloader, and when [re-]installing windows, just set the windows partition active, which would prevent the bootloader from being overriden during the install)
do you happen to have a bootdisk or a cd you can use to boot somekind of shell?