We study the behavior of dilute polydisperse polymer solutions in the good-solvent regime. We compute the second virial coefficient for polymers of different degree of polymerization and for general polydispersity distributions. We also determine the effective center-of-mass pair potential for polymers of different length. These results, combined with the integral-equation formalism and the hypernetted-chain closure, allow us to determine the osmotic pressure and the intermolecular structure function in the dilute regime for general polydispersity distributions.