Since I don't have a laptop which comes with a PCMCIA floppy drive (for instance Toshiba Libretto 100), I couldn't check this method. Please see the chapter Booting from a PCMCIA Device in the PCMCIA-HOWTO. Also I couldn't check whether booting from a PCMCIA harddisk is possible.
Anyway, when you are able to boot from a floppy and the laptop provides a PCMCIA slot, it should be possible to use different PCMCIA cards to connect to another machine, to an external SCSI device, different external CD and ZIP drives and others. Usually these methods are described in the documentation which is provided with the distribution.
The Sony Vaio (PCG-Z600) comes with an external USB-Floppy and an external CDROM (PCMCIA). You can boot from the CDROM, but afterwards Linux doesn't recognize the same drive anymore so that you can't install from it. You'll have to add the bootparameter linux ide2=0x180,0x360 (or 0x180,0x386?) at the LILO boot prompt if you want Linux to recognize a PCMCIA CDROM after the kernel has booted.