Unfortunately, there are a few reasons which might make it necessary to put DOS/Windows and Linux together on one laptop. Often the support for the flash ROM of PCMCIA cards and modems is not available for Linux, or you have to retrieve hardware information, which is not visible with Linux, due to a lack of support by some hardware manufacturers. I'm not sure wether this tasks can be achieved under an emulation like DOS-EMU or WINE.
If you want Linux with X, Netscape, etc., and Windows95, things will be tight in a 1GB harddisk. Though I do so with a 810MB disk.
Often you get a preinstalled version of Windows on your laptop. If you just want to shrink the Windows partition, you need a tool to resize the partition. Or you can remove the partition first, repartition, then reinstall. Most of the following information I found at the page of Michael Egan <Michael.Egan@sonoma.edu> at http://libweb.sonoma.edu/mike/fujitsu/ .
A well known and reliable, but commercial product is Partition Magic http://www.powerquest.com/product/pm/index.html from Power Quest.
Many people have used FIPS 15c (which may support FAT-32) http://bmrc.berkeley.edu/people/chaffee/fips/fips.html for repartitioning FAT partition sizes.) Also, another version from a different source is FIPS 2.0 (claims to support FAT-32) http://www.igd.fhg.de/~aschaefe/fips/ for repartitioning FAT partition sizes.)
One more "newer" utility for repartitioning and resizing FAT partitions is Ranish Partition Manager/Utility (FAT-32 support is claimed for this as well, Linux support is taken into account.) http://www.users.intercom.com/~ranish/part/ .
You may share your swap space between Linux and Windows. Please see "Dealing with Limited Resources" section. Also with Linux you can mount any kind of DOS/Windows partition. The other way round there are also some tools, for instance at http://uranus.it.swin.edu.au/~jn/linux/ , which provides a tool to read and write ext2 partitions from Windows9x/NT.
Also you can mount DOS drives of the type msdos, vfat and even compressed drives (Drivespace, etc.). For long file names use vfat and if you like autoconversion ( a nice feature for text files), you may do so by using the conv=auto option. I have used this in my /etc/fstab, but be aware this might cause some strange behaviour sometimes, look at the kernel docs for further details.
/dev/hda8 /dos/d vfat user,exec,nosuid,nodev,conv=auto 0 2
You may use the CD drive of a desktop (or copy the content of the CD to the hard disk) and connect both machines with a nullmodem cable. Than use a DOS boot floppy and the program INTERLNK.EXE to connect both machines.
Windows/NT offers: RAS - Remote Access Service
Windows/9x/NT offers the PPTP protocol to connect to remote sites via a TCP/IP tunnel. This protocol is also supported by Linux. PoPToP is the PPTP server solution for Linux allowing Linux servers to function seamlessly in the PPTP VPN environment. This enables administrators to leverage the considerable benefits of both Microsoft clients and Linux servers. The current pre-release version supports Windows 95/98/NT PPTP clients and PPTP Linux clients. The PoPToP pre-release server is not yet fully optimised. On release, PoPToP will be fully compliant with IETF PPTP Internet Draft and it will seamlessly support Windows PPTP clients with the full range of encryption and authentication features.
At The Notebook/2 Site by Dr. Martinus you may find information about different notebooks and PCMCIA cards working with OS/2.
The client side with DOS/Windows9x style operating systems seems to be no problem, since there are many PCMCIA cards with drivers for Netware available. For Linux connections see the mars_nwe package. Also the Caldera Linux distribtion is well known for its Novell support.
I hadn't time to build a Netware server on a laptop yet and couldn't check wether there are network connections possible (PCMCIA driver for Netware server).
The GNU Hurd is a totally new operating system being put together by the GNU group. In fact, the GNU Hurd is the final component which makes it possible to built an entirely GNU OS -- and Debian GNU/Hurd is going to be one such (possibly even the first) GNU OS. The current project is founded on the i386 architecture, but expect the others to follow soon.
The GNU Hurd Hardware Compatibility Guide states that Hurd should work on laptops, but PCMCIA support isn't ready yet.