Replacing Hdd on XPSm1530

Hey Guys,

So I have a good feeling the harddrive on my XPS m1530 is about to die. Naturally, I would want to be prepared to replace it so im doing the research now.

the current hdd:
Samsung Spinpoint M6 251JI 8mb cache 540RPM SATA 1.5Gb/s

what concerns me is the sata plug... are they all the same?
more recent lappy hdds are SATA 3Gb/s 16 mb cache or something on that line. so im wondering if a hdd like that would work with my laptop.
say I were to attach a Seagate Momentus 7200.3 320 GB, 16 MB Cache,7200 rpm would it work?

also... replacing the harddrive is easy right?
ive played with a normal PC hardware before but never really opened up a laptop

all sata 2.5" are the same, any 2.5" sata will work no matter what size and specs as long as it fits the size of the bay which is 2.5" standard for laptops thesedays
there are 3 laptop hard disk types

IDE: very old pins connection samesize as sata
Sata or sata 2: the same size as ide but they have just one long and one short conenction in plastic "no pins"
Mini Ide: half the size of 2.5" but very rare and used in sony and slim laptops