All right, you know the drill - 3 pages, 1 page cover, 1 page editorial/SRD, 1 page content, so let's take a look at 5 feats to modify mount spells!
-Aethon: This feat allows you to extend your harmless, personal ranged abjuration spells that specify a number of targets to the mounts the characters are riding, but only while they are riding. Not sure about this one: I usually handle riding animals as separate targets. The limitations help, though.
-Buraq: When casting healing (conjuration) spells on characters, their mounts are healed as well while they're in the saddle.
-Augment Steed: This feat enables you to forgo one or more of the steeds you conjure in order to improve your steed by granting the conjured, foregone steed's abilities like AC, movement etc. to the your regular steed. Additionally, your steed is not considered to be exerting itself while under the effect of the spell. An interesting and rather cool buffing-option for the spells, though one that has to be read very carefully by both players and DMs to avoid confusion.
-Heighten Steed Spell: By making the spell-level higher, you also improve the movement, AC and HP of the steeds. I think this feat is supposed to be a metamagic feat and lacks the [Metamagic]-descriptor, but I might be wrong here, since it actually increases the effective level of the spell it modifies. It depends on your perspective, I guess.
-Summon Steed: Each creature you summon with a summon spell can also come equipped with tack and saddle, willingly serving you or your allies as your mount. On the one hand, I really like this idea, on the other, the potential for goofiness is VAST - riding chokers and gibbering mouthers would e.g. also be possible, as would be riding elementals. A caveat that the creature has to have a place o actually sit on and be able to carry you would probably be in order.
Editing and formatting are very good, though not perfect - the wording of augment steed could have been slightly more precise and the yes/no-fringe regarding whether Heighten Steed Spell is [Metamagic] or not make it hard to judge. Layout adheres to SGG's 3-column standard and the BP comes mostly as no-frills and has no bookmarks, but needs none at this length. I'll just come clear - I'm not comfortable with Aethon and Buraq. Not because of their effects, but because of the internal logic of the world they tend to wreck: So casting the spell on dismounted beings make them count as two, but casting them on mounted beings makes it count as one? Can you see sick people being lifted up on sick horses during plagues to conserve both resources and money? I can and it's not a pretty sight. What I' m trying to go at - I think the feats herein NEED a closer definition on what constitutes a bond between rider and mount and limit the spells to respective teams. All in all, this BP provides ok feats, but I'm not truly sold on any of them apart from the Heighten Steep Spell- (metamagic?)feat. All in all, this BP feels slightly less polished than similar issues of the line and probably would have worked better as a full-blown mounted magic genius guide. My final verdict, thus, will be 3 stars - If you're like me and very keen on the consistence of the internal logic of your campaign, detract a star. If my gripes don't faze you too much, add one.