Lord Lucas has a new post on how to go about this here.
Other useful information: from Lord Lucas and how to address a Lord.
Also Write to Them for the Lords provides a searchable database of Lords by interest (number of times they have spoken on a subject) and by places they are associated with. 12 Lords come up when you enter "home education".
You can then click on each one and find out what they said on each occasion. Clicking on the heading for each of these takes you through to the context of the speech. Not all the references seem to bring up an exact quote but it is certainly useful.
Please make use of this resource to select the Lords you are going to contact. You can also check out which Lords have already been contacted here.
If you can find an email address for them, it might be better to use that rather than the fax facility on the TheyWorkForYouSite. This page lists all the Lords, along with the address of any web sites they have, though it does not say if they have email. However, if you click the 'biog' it gives you an email address if one is listed, or a personal fax number as well as their phone number (which seems to be a direct number rather than the HoL switch-board).
Of course if you prefer ink on paper then all the Lords share the same address:
House of Lords
See here and here for further inspiration on what you might say and how you could say it.
Please pass on this information to as many other people/lists as possible.