(The S in this name is pronounced like 's' in 'so', L like 'l' in 'girl' In the second spelling, SH is pronounced like a lightened 'sh' in 'she' i.e. like one between 's' in 'sand' and 'sh' in 'shaft'. )
Saalva or Shaalva was the name of a king whom the eldest princess of Kaashi , i.e. Amba loved. He was defeated by Bheeshma on the occasion of her abduction. when bheeshma learnt that Amba loved Saalva, he sent her to Saalva to get married. Saalva, of course, denied the offer pleading moral grounds. That denial made Amba's life miserable and she decided to take revenge on Bheeshma.
There was another Saalva, who invaded Dvaaraka in Krishna's absence with his magical flier Soumbhaka , but was later killed by Krishna.
Also, one king Saalva was mentioned by Drupada , in Udyoga parva. It is not clear whether these two were different or the same person.
Again, Saalva was the name of a kingdom in the days of Mahaabhaaratham.
The reader should remember the words like this , with difference in meaning or reference, but with similarity in spelling and thereby similarity in pronunciation too.