A 15th level fighter afflicted with lycanthropy (waretiger), would have 20 HD and effectively be a 23rd level character due to the ECL adjustment of afflicted waretiger template. That means that for the purposes of gaining experience, you need the amount required for a 24th level character to get to the next level, AND when determining experience gained, you go off the 24th level column when comparing the CR/EL.
You'd have 15d10+5d8+ (CON BONUS x 20) hit points. Only your first HD in fighter would be maximized.
As far as skills, you have 15 levels of your fighter skills as normal. You also have 5 levels where you gain 2+int modifier skill points that can be used freely in any of the lycanthropes listed skills, which are considered class skills: Balance, Climb, Handle Animal, Hide, Listen, Move Silently, Spot. You may distribute your 5 HD of points as you choose in these, or cross-class if you like.
Your abilities are augmented by the lycanthrope template giving you: Str +12, Dex +4, Con +6
As far as your BAB, you have 5 HD of "Humanoid" which is considered to go off the base attack bonus of a cleric (3/4). So, you get +3 from your lycan levels. You now have a total of +18 base before adding your strength bonus.
For feats, you gain all of the feats listed for the waretiger: Alertness, Combat Reflexes, Improved Initiative, Improved Natural Attack (bite, claw). That is a net gain of 5 feats. Fighter Feats are in a category of their own, so at this level you should have 7 feats. If you already had any of these feats, mark them off this list. Add up the total number of feats gained after adjusting for feats you already had. Add in the feats you gained from normal leveling (not fighter). If this is less than 7 feats, you may choose feats normally available to any character to bring it up to 7. If it is more than 7, than the extra feats you gained are considered bonus feats, and from this point on, you still gain a feat as normal. You are not in debt.
You also gain Iron Will as a bonus feat that does not figure into that equation above.
More in a bit... Off to a meeting.