Why this? Unfortunately Linux users are not always supported with the necessary hardware information. Sometimes it is possible to look at this informations in Window$95. Sometimes its even useful to connect the two. Linux could also provide occasional access point services to a Window95 laptop of a friend dropping by.
Where to get it from? At http://www.microsoft.com in the directory /Windows95/downloads/contents/WURecommended/S_WUCommunications/W95IrDA / you will find a support pack Infrared Transfer 2.0. It is a self-extracting archive W95IR.EXE with 331KB. Note: Microsoft seems to change the location of this file (and others) at random, the former URL is Microsoft Windows95 IrDA - Old
Microsoft(tm) has three versions of IrDA support for Windows95. The version number can be found in the "Software" icon in the Control Panel and the file infrared.inf.
Version 1.0 is still delivered with some hardware.
Version 2.0 is the version they currently offer at their web site. It is in the self-extracting file W95IR.EXE. The last time I looked (1999-02-21) it was 434KB and was found at http://support.microsoft.com/download/support/mslfiles/W95IR.EXE . Their website is frequently changing, so do not be surprised to find the file (also) in another location or not at all.
Version 3.0 can/could be found in their downloadable Infrared development kit IRDDK30, but is mostly useful for developers. It is internally different from 2.0, it is based on "miniport" network drivers, just like the Linux version. It exists for some time and has some support for NT, but it clearly did not make it into the mainstream NT4.0 distributions. For 95 you are probably better off with 2.0. The choice may depend on the documentation of the drivers you get with your specific hardware.
MS website also used to contain a nice utility IrXfer, contained in the archive IRXFER.EXE, This is the Infrared Transfer utility, which uses an IrOBEX variant I think, it is referenced in the IrOBEX protocol description. The utility was freely downloadable, but I could not find it the last time. It is a nice graphical utility which can be used to transfer files over IrDA between computers.
With some machines, e.g. a HP Omnibook 800 it is necessary to use a vendor specific version of this package (for the HP Omnibook 800 you may find it on the recovery CD).
Especially the ..\windows\inf\*.inf files and the device manager are of interest to look for configuration details.
As far as I know Window$NT doesn't support IrDA(TM). About Window$98 I have heard there is no IrDA(TM) support yet. Countersys on http://www.countersys.com claims to sell an IrDA solution for NT4.0 to support their JetBeam product, Microsoft refers to them for it.
AFAIK:
Windows95 : use 2.0
Windows98 : delivered with 3.0 and IrXfer (works with Linux/IrDA, IrOBEX?)
WindowsNT4.0: no IrDA
Windows2000 : 3.0(+?) http://www.microsoft.com/hwdev/infrared/
There are also some non M$ products available. Note: Some of them use proprietary infrared protocols:
CounterPoint: QuickBeam 1.15 (works with Linux/IrDA, IrOBEX?)
LapLink 7.5
CarbonCopy 32 4.0
pc ANYWHERE 7.5
Puma Technology: TRANXIT pro 4.0
Ha Duong Minh: Today I am delighted to report that ircp from the openobex project, http://sourceforge.net/projects/openobex/ works like a charm to transfer files between my linux box and its win98 cousin. It can't be simpler: ircp file1, file2, ... or: ircp -r [DEST] Send files over IrDA. Use -r to receive files.