sorry, but i never read any faqs to get it started, so i cant reccomend one... BUT i use Nlite and it has more than enough options.
I will suggest to you not to actually change much if you want to do a slipstream. All i do is put in my key automatically and add service packs and updates. Ive tried other options, but unless you want to do some really rigorous testing (like in vmware or something) then i wouldn't bother. For the basics, its drag and drop then click "make Iso". You really can't go wrong.
im not certain, but if you have a recovery partition, that means you don't have an install disk. extracting windows might be a pain, but if it dosent work you may be allowed to use your existing key with somebody elses XP home, but u'd have to ring microsoft - they might even post you ur own xphome cd. (don't hold ur breath, but it happened once)
You own the cdkey, so the license is yours.
Also you may find that your motherboard drivers and stuff are intergrated within the OS on the recovery partition, happened to me once, finding the drivers again was a pain, but possible. In short, if you get stuck, its a bit debateable wheather you are legally allowed to post things like this on here with a great level of absolution. "hint"
Also , concerning your linux/windows issue, i use a program in windows called EXT2fs to read my linux partitions - tho they have to be ext3 not reisers. i find it really reliable. in linux i use ntfs-3g and it mounts my win partitions read/write, never had a journal error or lost data.
So you could have:
hda1 ntfs 65G: XP-Home
hda2 ext3 10G: /root
hda3 ext3 4G: /home (i never use 4 gigs worth of home on my dual boot machine - EVER)
hda5 swap 1G: (eh, if you got it, why not)
You will have heaps of room. 15 gigs for windows isnt much when u got ur updates on, office installed, some fancy apps and maybe WoW or BF2 lol