Most of this post, if not all of it, has been posted elsewhere as responses to questions. However, I felt it necessary to gather all of this very helpful information into one place, to help answer people's questions.
Earning Unlocks:
Unlocks are still earned by ranking up. The first two unlock ranks, Lance Corporal and Corporal, still only give you ONE unlock. After that, Sargeant through Master Gunnery Sargeant/Sargeant Major, give you TWO unlocks EACH. This is because there are only five new unlocks in SF, as opposed to the seven available in vanilla BF2
Using Unlocks:
There are effectively two tiers of unlocks now. The first tier is composed of all the original unlocks from vanilla BF2. For exaple, the G3 for the assault class. The second tier is composed of all the new SF weapons, for example, the F2000 for the assault class. To unlock ANY weapon from the second tier, you MUST unlock the corresponding weapon FOR THAT CLASS from the first tier. For example, to unlock the F2000, you must first unlock the G3
PLaying with yoiur new toys:
First things first: once you unlock ANY weapon, it can be used in vanilla BF2 for ANY team. This does NOT stay true in SF matches. In an SF match, you CAN use any unlock from the first tier, mentioned above, for any team. However, you CANNOT use the new SF unlocks. These are some of the default weapons for some teams. For instance, the SAS get the F2000, G36E, MG36, and more as default weapons. The SEALs get the Scar-L as default for the Special forces classes. However, other teams such as the Rebels, Insurgents, and Spetnaz will not be able to use ANY of the new SF weapons at all, even if you have unlocked them. The SF weapons you spent an unlock on are only truly "unlocked" for vanilla BF2.
I hope this answers many of the questions floating around out there.
Earning Unlocks:
Unlocks are still earned by ranking up. The first two unlock ranks, Lance Corporal and Corporal, still only give you ONE unlock. After that, Sargeant through Master Gunnery Sargeant/Sargeant Major, give you TWO unlocks EACH. This is because there are only five new unlocks in SF, as opposed to the seven available in vanilla BF2
Using Unlocks:
There are effectively two tiers of unlocks now. The first tier is composed of all the original unlocks from vanilla BF2. For exaple, the G3 for the assault class. The second tier is composed of all the new SF weapons, for example, the F2000 for the assault class. To unlock ANY weapon from the second tier, you MUST unlock the corresponding weapon FOR THAT CLASS from the first tier. For example, to unlock the F2000, you must first unlock the G3
PLaying with yoiur new toys:
First things first: once you unlock ANY weapon, it can be used in vanilla BF2 for ANY team. This does NOT stay true in SF matches. In an SF match, you CAN use any unlock from the first tier, mentioned above, for any team. However, you CANNOT use the new SF unlocks. These are some of the default weapons for some teams. For instance, the SAS get the F2000, G36E, MG36, and more as default weapons. The SEALs get the Scar-L as default for the Special forces classes. However, other teams such as the Rebels, Insurgents, and Spetnaz will not be able to use ANY of the new SF weapons at all, even if you have unlocked them. The SF weapons you spent an unlock on are only truly "unlocked" for vanilla BF2.
I hope this answers many of the questions floating around out there.